Developing Lead-Free Microelectronics

December 13, 2010
School of Engineering, Coimbatore

All around us we see electronic devices shrinking in size at an astounding rate. Computers, TVs, I-pods, hard disks, pen drives, mobile phones now pack more features and provide faster performance in ever smaller and lighter models.

“When we pack many tiny electronic devices into a small volume, too much has to happen in too small a space,” explained Dr. Murali Rangarajan of the Department of Chemical Engineering and Material Sciences at Coimbatore, who will work on a new DRDO-funded research project.


Dr. Murali will be joined by Dr. T. Ramachandran, Professor, Department of Chemistry and Dr. Krishnashree Achuthan, Professor, Department of Chemical Engineering and Materials Sciences in executing the project.

“In such small devices, it is a tremendous challenge to ensure that all the processes happen smoothly without any mechanical or electrical or thermal breakdowns,” added Dr. Murali.

It is in this context that the team will seek to develop novel softer, compliant solder materials that ensure better mechanical and electrical stability. Particularly the team will explore the development of lead-free compliant solder materials for micro-fabrication.

Lead is highly toxic heavy metal; alternate materials can offer more environmentally benign alternatives in micro-fabrication.

“Materials development for micro-fabrication is one of the most cutting-edge and exciting areas of research to pursue today,” enthusiastically stated Dr. Murali.

The team will receive support from Dr. Madhav Datta of IBM, recognized internationally as an expert in micro-fabrication.

Titled Electrochemically Tailored Compliant Solder Materials for Flip-Chip Joining, the project has already received a grant of 62.48 lakh from the DRDO. Work will be undertaken over the next three years at the Materials Chemistry and Research Laboratory at the Coimbatore campus.

Lead-Free Microelectronics“We are in the process of procuring an electrochemical workstation, power supplies, an optical microscope and polishing and grinding equipment,” shared Dr. Murali. “We will also hire research fellows (JRF/SRF); we expect that they will complete their Ph.D. at Amrita, while working on this project.”

There are no international standards today for developing lead-free microelectronic devices. The efforts of the Amrita team will be geared towards setting up international standards.

While the main goal of the project is to develop soft, compliant, lead-free, low-melting temperature solder materials by electro deposition, applicable in flip-chip technology for microelectronic packaging, the project has a number of other objectives, as well.

“Our first objective is to gain a fundamental understanding of the electro deposition behavior of low-temperature solder materials such as tin, bismuth, indium and their alloys,” noted Dr. Murali. “Secondly, we will apply optimized plating conditions to fabricate an array of isolated solder bumps applicable in flip-chip interconnections.”

“Finally we hope that this project will initiate further research in our department in the areas of electronic materials and structures applicable in microelectronic packaging.”

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