Efficient and Precise 3D Integration of Heterogeneous Microsystems from Fabrication to Assembly

Research group:
prof. dr. ir. A.J. Huis in' t Veld, G.B.R.E. Römer, MSc R. Pohl

Project term:
May 2010 - May 2013

3D integration, die-to-wafer, die-to-die, self-assembly, microassembly, hybrid assembly

Project Description

FAB2ASM is a research project funded by the European Committee, which tackles a major problem in 3D integration that currently limits industrial take-up: high throughput and high accuracy 3D integration of miniaturized dies onto dies or substrates. This issue is important for 3D integration of microelectronics and microsystems. 3D integration will take off in the next 5 years in all measures including total number of devices, the market share, as well as the density of the connections. The state-of-the-art integration technology for 3D microsystems relies on robotic pick-and-placing machines and machine vision, which cannot achieve simultaneously high-speed and high-precision. If high precision e.g. a micron is needed, either the cycle time of integration can be very long, from e.g. over ten seconds to minutes, or even not achievable. The objective of the FAB2ASM is to develop highly efficient and precise die-level component integration technology based on hybrid assembly technology that joins robotic tools and self-alignment and corresponding interfacing methods for multi-functional microsystems. In contrast to most explorative self-assembly technology developed to-date, FAB2ASM attempts to develop a highly industry relevant technology that reuses most of the industrial process steps, but on the other hand dramatically improves the performance of the integration process in the precision and efficiency chart. FAB2ASM will allow handling small (100 μm) and/or thin dies (20 μm), ultra high speed assembly (40,000 UPH), and flip-chip capabilities, while ensuring industry proven reliability. Led by AALTO, this consortium of 5 research centers and 3 industries will join force to fulfil this urgent and important need of industry in 3D integration, and will demonstrate the merits in three industry led demonstrators: one manufacturing equipment demonstrator, one photonic IC demonstrator and 3D microelectronics demonstrator.


Within the framework of the FAB2ASM project, the Chair of Applied Laser Technology investigates novel laser based processes aiming on the creation of low density Through Silicon Via’s (TSV), as well as of surface textures or fluid driven self-alignment. Furthermore, an alternative laser based process to fill the TSV’s is investigated.

Project Approach

  • TSV filling: Laser-Induced Forward Transfer (LIFT) is a direct write method that can be used to deposit metal droplets in the order of 350 nm in diameter. Using the LIFT technique multiple droplets will be used to subsequently fill TSV’s. However, for industrial applications the quality of the deposited droplets i.e. shape and especially the amount of contamination has to be improved further.
  • Surface texturing: Using ultra-short laser pulses, well controlled superimposed micro- and nano-scaled surface textures can be obtained. By controlling the surface structure on the micro- and nano- scale, the natural hydrophobicity of materials can be modified. These surface textures facilitate fluid driven self-alignment.

Isometric representation of a typical laser-created receptor site of 100×100 µm2 for fluid drive self-alignment.


Current studies focus on a deeper understanding related to the governing physics of the LIFT process. In particular the release process of liquid metal droplets and micro jets during the very early stage of the process are studied. Preliminary experiments using high-speed imaging techniques as well as first trials on the TSV filling have successfully been performed.


The FAB2ASM is carried out with financial support of the European Union Seventh Framework Programme FP7-2010-NMP-ICT-FoF under Grant Agreement No. 260079 - Efficient and Precise 3D Integration of Heterogeneous Microsystems from Fabrication to Assembly.


(of the Chair of Applied Laser Technology in FAB2ASM)

  • Pohl, R. and Römer, G.R.B.E. and Huis in 't Veld, A.J. (2012) Laser processing in 3D Integration of Heterogeneous Microsystems. In: Industrial Technologies 2012; Integrating nano, materials and production, June 19-21, 2012, Aarhus, Denmark.
  • Römer, G.R.B.E. and Arnaldo del Cerro, D. and Jorritsma, M.M.J. and Pohl, R. and Chang, B. and Liimatainen, V. and Zhou, Q. and Huis in 't Veld, A.J. (2012) Laser micro-machining of sharp edged receptor sites in polyimide for fluidic driven self-alignment. In: 13th International Symposium on Laser Precision Microfabrication, LPM 2012, June 12-15, 2012, Washington, DC, USA.
  • Römer, Gert-Willem and Jorritsma, Mark and Arnaldo del Cerro, Daniel and Chang, Bo and Liimatainen, Ville and Zhou, Quan and Huis in 't Veld, Bert (2011) Laser micro-machining of hydrophobic-hydrophilic patterns for fluid driven self-alignment in micro-assembly. In: 12th International Symposium on Laser Precision Microfabrication, LPM 2011, June 7-10, 2011, Takamatsu, Japan.

Contact person(s)

R.Pohl, MSc.
University of Twente
Faculty of Engineering Technology
Chair of Applied Laser Technology
Building: Horstring (Building No. 21), Room: W.230
Postal address: P.O. Box 217, 7500 AE, Enschede, The Netherlands
Phone: +31 (53) 4893532
Secretary Ms. Tjapkes: +31 (53) 4892502
Fax: +31 (53) 4893631