23 September 2018
Published online 14 February 2017
Researchers present a new etching technique that combines a soft and hard mask in a single entity.
Scientists have created a hybrid technique where, according to them, “anyone with a basic knowledge of electronics will be able to easily assemble application-oriented electronic systems.”
Mohamed Ghoneim and Muhammad Hussain, from King Abdullah University of Science and Technology, Saudi Arabia, want to promote the advent of DIY electronics. Assembling electronics is currently a sophisticated, complex method, says Hussain, the principal investigator of this study, but their technique makes it easier.
Surface micromachining involves the deposition and etching of different structural layers on top of the substrate, allowing the production of microstructures. Physically flexible, stretchable, and reconfigurable microstructure electronics plays an important role in fields such as 3D integrated circuits, dynamic random access memory capacitators, micromechanical systems, and metal oxide semiconductor technology.
But flexible electronics require deeper etching. This, in turn, requires the use of hard masks that impose manufacturing limitations, some of which this study in Small addresses1.
The scientists introduce the use of a novel hybrid mask composed of a sacrificial layer and a hard mask, which enables deep sub-millimetre etching.
The sacrificial layer, which is easy-to-etch is not suitable for prolonged deep etches as it is consumed fast. However, when made of soft materials, such as polymers, the surface roughness of underlying layers is preserved and the lower layers are not contaminated. Further, the sacrificial level can be easily removed by immersion in organic solvents, such as acetone.
The use of the hybrid mask allows a high aspect ratio, while preserving existing devices and structures making this approach advantageous for precise dicing, making irregular-shaped dyes, and novel packaging techniques, including Lego-like concept for pre-packaging modules and system integration.
The research team is currently investigating a disruptive approach that will allow these Lego-like electronics to self-assemble.
- Hussain, M. T. & Ghonein, M. M. Highly manufacturable deep (sub-millimeter) etching enabled high aspect ratio complex geometry lego-like silicon electronics. Small http://dx.doi.org/10.1002/smll.201601801 (2017).