Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Microelectronics: Taking the heat off microfluidic chips

Replacing a high-temperature processing technique with an infrared treatment allows the manufacture of tiny devices without damaging the polymer components
Microfluidic devices are allowing microelectronic engineers to shrink laboratories to the size of a computer chip. By ferrying reagents through a series of microscopic channels and reservoirs carved into a flat plate, researchers can develop new chemical reactions or monitor the cellular effects of drugs on a much smaller scale, potentially saving time and money.

Some of these microfluidic devices even have electrical components that act as heaters or sensors, for example. But researchers have struggled to develop a rapid, low-cost method for creating the detailed metal patterns that make up these circuits.

Conventional techniques tend to require high-temperature processing, which can damage the transparent polymers typically used to build microfluidic devices, such as polycarbonate (PC) or poly(methyl methacrylate) (PMMA). Despite this drawback, the polymers are preferred over more robust alternatives because they “have very good optical properties, which most microfluidic devices require, and they are viable for plastic injection molding, which enables high-volume production,” explains Zhaohong Huang of the A*STAR Singapore Institute of Manufacturing Technology.

Huang and his co-workers developed an alternative process that avoids exposing the polymers to high temperatures, and used it to build complex metal-patterned microfluidic devices (see image)1. They first covered sheets of PC or PMMA with thin layers of chromium, copper and nickel, and added a coating of a light-sensitive material called a photoresist. At this stage, the 'sandwich' would normally be baked at around 100 °C to remove any residual solvents after the coating process. But these temperatures would soften and warp the polymer, potentially cracking or loosening the metal layer.

Instead, Huang’s team used infrared heating elements to eliminate the solvents. The metal layer acted as a protective barrier, reflecting more than 95% of any infrared radiation that hit it, meaning that the radiation warmed the photoresist layer but not the polymer beneath.

The researchers then used standard photolithography processes to create the microfluidic device. They placed a patterned mask over the sandwich and shone ultraviolet light to erode some areas of the photoresist; then, they etched away the exposed areas of metal beneath using a wash of chemicals. Stripping off any remaining photoresist left a clean metal pattern, which had features as small as 10 micrometers in width.

“If the surface finish is gold, our method can cut costs by more than 90%,” says Huang. His team is now refining the process, and creating patterns of different metals with catalytic properties, which could speed up chemical reactions inside microfluidic devices.

The A*STAR-affiliated researchers contributing to this research are from the Singapore Institute of Manufacturing Technology

Journal information

Huang, Z. H., Lim, B. C. & Wang, Z. F. Process development for high precision metal patterning on low glass transition polymer substrates. Microelectronic Engineering 98, 528–531 (2012).

A*STAR Research | Research asia research news
Further information:

More articles from Process Engineering:

nachricht Applying electron beams to 3-D objects
23.09.2016 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

nachricht New process for cell transfection in high-throughput screening
21.03.2016 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Enormous dome in central Andes driven by huge magma body beneath it

25.10.2016 | Earth Sciences

First time-lapse footage of cell activity during limb regeneration

25.10.2016 | Life Sciences

Deep down fracking wells, microbial communities thrive

25.10.2016 | Earth Sciences

More VideoLinks >>>