From recycling to a second-hand chip

With increasing digitalisation, the number of semiconductor products ending up in the waste is also growing. Recycling or re-using them not only helps in terms of sustainability, but is also increasingly interesting as a source of raw ­materials, too.

According to the latest issue of the “Global E-Waste Monitor” from the United Nations, a record amount of 53.6 million tonnes of electronic waste was generated in 2019 around the world. And this is set to increase even more – to 74 million tonnes by 2030. Compared to 2014, this would mean the amount of electronic waste almost doubling in just 16 years. In 2019 only 17.4 per cent of this was collected and recycled. This means that gold, silver, copper, platinum and other high-value, recyclable materials (which are conservatively estimated at 57 billion US dollars – an amount that is more than the GDP of most countries) are mostly disposed of or burned, instead of being collected for recycling.

Reducing the environmental impact 

Of course, the proportion of semiconductor products in electronic waste is relatively low. However, more and more companies are aiming to become more sustainable in this regard and reduce their CO2 footprint down to zero and “… yet often lack the data to decipher the IC part end-to-end. That is where imec comes in. We have that data, and are ready to support the industry with all necessary insights, tools, instruments and numbers,” says Luc Van den hove, CEO of imec. The research and innovation centre for nano-electronics and digital technologies has specifically launched a research programme called Sustainable Semiconductor Technologies and Systems (SSTS). The SSTS programme is the first initiative to bring together stakeholders from the entire IC value chain to record the environmental impacts of chip production.

Here, there is an increased focus on recycling – this is the only way to reduce the amount of e-waste and recover important raw materials. It is not just environmental reasons that justify recycling measures, however. Elements such as tantalum, neodymium, tungsten, cobalt and gallium really are valuable materials because they are rare, have a high economic significance and are also associated with a significant supply risk. Recovering them could also play a part in more resilient supply chains.

New recycling processes

However, at the moment, recycling chips is still too expensive and time consuming due to its complicated set-up. New recycling concepts are necessary to reduce costs but applicable processes are still mainly in the research stage. As part of the EU ADIR project, for example, a procedure has been developed that can be used to efficiently disassemble electronic devices at the end of their useful life into their component parts thanks to flexible processes that can be automated. To this end, laser technology, robotics, vision systems and information technology all work together intelligently in a disassembly plant. In the process, lasers identify substances, unsolder components contact-free or cut them out of printed circuit boards. Strategically important recyclables with a high economic significance can thus be efficiently recycled on an industrial scale. It was possible, for example, to recover 96 to 98 per cent of the tantalum. Another example is an environmentally friendly hydrothermal separation process developed by Lu Zhan’s team at the East China Normal University. It was possible to recover 99.9 per cent of the gallium and 95.5 per cent of the arsenic from ICs using it.

A completely recyclable transistor

New materials could also make recycling much easier, at least in some sectors. Researchers at Duke University in the USA have developed the first completely recyclable transistor. The printable building block is created from a conducting graphene ink, a semiconducting ink based on carbon nanotubes, as well as an insulating nanocellulose ink. It is easy to recycle the carbon-based component, and only requires an ultrasonic bath and a centrifuge. The graphene and carbon nanotubes, which can each be recovered by over 95 per cent, can then be used for printing another device.

Re-using semiconductor components 

Re-using semiconductor chips such as memories and ICs as a whole – as “second-hand chips” – would be even more efficient and environmentally friendly than recycling. This requires the right disassembly processes, and semiconductor products must be designed to be easily disassembled. New standards and collaboration with the industry are also crucial to creating a transparent secondary market for re-used microchips, as Dr Patrick Schröder from British think tank Chatham House highlights: “Semiconductor companies should consider a ‘certified second-hand chip’ mechanism where they are actively engaged in the validation process to prevent counterfeiting and national security issues.”

In the long term, a comprehensive sustainability vision is needed for the semiconductor industry which takes into account both environmental concerns as well as the resilience of the supply chains. Core elements are the design of semiconductors and electronics for re-use, the operation of waste-free production plants, the development of a well networked infrastructure for electronic repair centres on a global level, and avoiding unnecessary waste by recycling used parts and components. “I would like to call upon the whole semiconductor value chain not to stand at the side, but to act as one and to join forces with us to cut back the entire semiconductor industry’s ecological footprint,” Luc Van den hove, CEO of imec adds.