MSc thesis project proposal

Conductive Through-Polymer Optical Vias (TPOVs)

The need for more functionalization, miniaturization and lower energy consumption drives the ongoing semiconductor industry. Vertical interconnects for 3D integration takes advantage of the shorter total length of the interconnect, lower resistance, reduction in the signal delay and avoidance of parasitic inductances. As one of the states of the art vias, through-mold via (TMV) is usually formed using a process for epoxy-molding compound drilling and residue cleaning. To reduce the diameter of vias, increase aspect-ratio as well as decrease resistance, through-polymer via (TPV) is developed for 3D integration and packaging. Unlike conventional TMVs, in TPVs, the pillars are fabricated with metal plating at first and then encapsulated inside an epoxy molding compound.

In the past few years, research at the Electronic Components, Technology and Materials (ECTM) of TU Delft has developed a mature TPV technology with strong collaboration of Boschman, which is a world-leading company of film-assisted molding (FAM). One drawback of the current TPV technology is the metallization layer makes vias opaque to visible lights, whereas optical windows are vital to applications such as light-emitting diodes (LED), organic electroluminescent diodes and optical detectors. Conductive nanoparticles additives, such as TiO¬2, enable photoresist great electrical conductivity but keeping excellent transparency. Thus, the complicated metallization steps after photoresist pillar fabrication can be removed.

This project aims to develop conductive through-polymer optical vias (TPOV). Building onto the group’s knowledge, the project will help develop a deeper understanding of mixing nanoparticles with photoresists and processing aspects of conductive TPOV towards 3D integration of optical devices.


This hands-on project will include:
  • An extensive review of the related state-of-the-art;
  • The development on the reformulation of photoresist (SU-8);
  • Mastering the process flows for TPOV fabrication developed at the Else Kooi Lab (EKL) of TU Delft;
  • Measurement of the diameter and aspect ratio of the vias;
  • Characterization of the electrical and optical performance of the vias;
  • Comprehensive reporting of the full experimental work.
  • Requirements

    You are an ambitious master student looking for hands-on experience and a multidisciplinary thesis project on microfabrication and nanomaterials. You have a microelectronics, chemistry, nanotechnology or material science background and like experimental lab work. Good communication skill in English and a pro-active attitude are expected.


    MSc Dong Hu

    Electronic Components, Technology and Materials Group

    Department of Microelectronics

    Last modified: 2020-05-16