IISC’s invention and its application in Nano-electronics industry

As per this news, IISC’s scientists have found out a method to lay circuits in electronic chips which would be both cost effective and energy efficient. They have devised a methodology to etch nano-circuits on silicon chips at room temperature, which has a potential to boost the research efforts at fundamental chip level.

What are nano-circuits?

Electrical circuits which operate on the nanometer scale are called nano- circuits. They are several thousand times thinner than a strand of hair. These circuits acts as basic building blocks of all high end devices like TV’s, aircraft, mobile phones etc.

What is nanoelectronics? How it can improve the capabilities of electronic components?

Simply put, Nanoelectronics is nothing but application of nanotechnology in the field of electronics.  Nano electronics helps to reduce the weight and power consumption of electronic devices among others and improves the capabilities of the devices.

Why the invention is important? What are its advantages

Industrial applications

The invention has a potential to cut down the patterning cost and reduce the cost of optical lithography and e-beam lithography. This invention uses a new way to etch thin lines on a substrate using electrodes and is called as electrolithography. It will be very useful in inscribing nanometer scale circuits which are used to make IC chips, minute transistors among others.

Cheap and energy-efficient

If this model is developed into prototypes for commercial use, it could reduce the cost of the equipments from 5 crores rupees per piece to 15-20 lakhs rupees per piece. Moreover this technology is energy efficient and entails less operating costs.

In the field of research

This technology has the potential to surpass the existing state-of-the-art technologies and will be useful in academia too as more educational institutions will be able to afford research in nanotechnology.

Environment friendly

This technology is more environment friendly than the existing ones as it does not require high currents or vacuum atmosphere.

Processes involved in lithography

In the process of lithography, a layer of suitable polymer is coated over a transparent glass plate. A layer of chromium is added on top of this and a trench of the desired pattern is dug out on the chromium layer. This results in the exposure of the parts of the polymer layer. Then acetone is used to dissolve the exposed polymer and remove them causing a gap to be formed in the polymer-chromium sandwich. This whole assemblage will function like the negative of a developed photo film and when the metal of choice is sputtered onto this sandwich it will directly fall on the glass plate and occupy the gap that has been created. With this the desired pattern using a metal of choice can be formed.

At present the electric circuits are etched by 2 methods:

• Electron-beam lithography/e-beam lithography.
• Optical lithography/photolithography.

These technologies evolved during the semi-conductor revolution of 1960s. In these techniques, the circuit is etched on polymers.

In e-beam lithography, a focused beam of electrons are used to draw shapes on the surface covered with electron sensitive film. By changing the solubility, the electron beam selectively removes the exposed or non-exposed regions when immersed in a solvent. This creates very small structures which are then transferred to substrate material through etching.

In opticallithography, light is employed to transfer the pattern from the photo-mask to a light sensitive chemical on the substrate. Further some chemical treatments are done either to engrave the exposure pattern into it or deposit a new material upon the desired pattern.

What is the difference between the existing techniques and the invented technique (electrolithography)? How this invention is an improvement upon the existing ones?

The manner of digging the trench is the crucial difference between the existing processes and electrolithography. In the existing technologies the circuits are etched on polymers but the new technique involves doing the same on metal, making it much easier to etch. Here, electrodes are used. The very thin cathode causes the chromium to heat up, dissolve and flow out when moved like a nib over the chromium layer. This creates a trench, which is different and efficient from the existing ones.

What is the future scope of this invention?

At present, companies like Qualcomm, Intel, MediaTek etc. are using nano-circuits in the chips they manufacture. They are exploring ways to pack more capacity into the chips along with reducing the size of the chips. This new invention can go a long way in helping them to manufacture such chips until their own research produces concrete results.