Marco Barink

Prediction of the thermo-mechanical material behavior of PEN foil during photolithographic processing

Flexible substrates (polymers) for plastic electronic products are far less stable to environmental factors, like heat and moisture, than currently used non-flexible substrates (silicon). This introduces problems during the lithography process of these products. This study presents a thermo-mechanical model of PEN foil; an organic material often used as flexible substrate for plastic electronics. The model is validated with experimental foil behavior during a loading experiment and with the experimental bending behavior in a foilon-carrier situation. These kind of models are useful as they can be used to predict and to optimize lithographic process steps.

Modeling the residual shrinkage during lithographic processing on flexible polymer substrates

The challenge of lithographic production of electronic circuitry on polymer foil is that deformations approaching the feature sizes of the circuitry can cause considerable overlay problems and thereby malfunctioning of the devices. The substrate foil is susceptible to several types of deformations. Accurate prediction of these deformations is of great importance, as it will help to improve the production process and thereby improve the quality of the electronic devices. One of the deformations is the residual shrinkage, a deformation that occurs after application of a heat step to a polymer foil. This study presents an experimental investigation of residual shrinkage combined with a modeling approach in which the temperature dependent visco-elastic material properties of the foil are used. The model enables us to more accurately predict overlay errors.

The electro-thermal-mechanical performance of an OLED: A multi-physics model study

In order to study the electrical-thermo-mechanical interaction in OLEDs, finite element based simulation models were developed. Two dimensional models were used to study detailed design effects, such as the location of the bus bars, while a three dimensional model was used to study the effect of differences between the two and three dimensional models, as well as bus bar designs.

Integrated Front–Rear-Grid Optimization of Free-Form Solar Cells

Free-form solar cells expand solar power beyond traditional rectangular geometries. With the flexibility of being installed on objects of daily use, they allow making better use of available space and are expected to bring in new possibilities of generating solar power in the coming future. In addition, their customizable shape can add to the aesthetics of the surroundings. Evidently, free-form solar cells need to be efficient as well. One way to improve their performance is to optimize the metallization patterns for these cells. This work introduces an optimization strategy to optimize the metallization designs of a solar cell such that its performance can be maximized. For the purpose of optimization, we model an existing transparent free-form solar cell design, including front and rear electrode patterns, to validate it against previously published experimental results. The front and rear metallizations of this transparent free-form solar cell are subsequently redesigned using topology optimization. More than 50% improvement in output power is achieved by using topology optimization.

Hybrid integration on low-cost flex foils using photonic flash soldiering

Soldering of packaged electronic components using industry standard Sn-Ag-Cu (SAC) lead-free solders on low-cost foils, which are often the substrate of choice for flexible electronics, is challenging. This is mainly originating from the fact that the reflow temperatures of these solder alloys are normally higher than the maximum processing temperature of the low-cost flex foils. To enable component integration on the low-cost foils a novel method for soldering has been introduced by Holst Centre as an alternative to oven reflow, termed “photonic soldering”. In this method high intensity photonic flashes are used to deliver the thermal energy required for soldering. By taking advantage of the selectivity of light absorption, the required energy for soldering is delivered to the components and circuit tracks while excessive heating of the foils is avoided. This paper presents successful photonic flash soldering of packaged LED components on low-cost polyethylene terephthalate (PET) foils using conventional SAC solders as a demonstration of the capabilities of this novel soldering technology.