Periodic Reporting for period 2 - SPRING (Scalable Production and Integration of Graphene)
Periodo di rendicontazione: 2021-04-01 al 2023-09-30
The global economy depends on semiconductor devices – electronic chips – in everything from smartphones to cars, the internet to lifesaving medical equipment. This market has been driven by an exponential increase in capacity achieved through miniaturisation, now reaching its physical limits. Graphene, a one-atom thick carbon layer is seen as having the greatest potential for semiconductor improvements. However, the adoption of graphene is impeded because there is no production and transfer technology which delivers high quality graphene and is suitable for large scale production processes. Applied Nanolayers (ANL) - founded in 2012 by seasoned industry professionals & material scientists from Leiden University - is unique in developing the technology to produce and exploit quality graphene on an industrial scale. Large tool vendors, supplying tools that enable semiconductor companies to get maximum performance from the current silicon technology, have not built growth and transfer tools for graphene. Therefore, in addition to developing a production methodology, ANL has built its own tools, using existing tool platforms. This means that the ANL processes can be seamlessly integrated into mainstream industry fabrication partners. ANL has a proven automated growth process as well as a dry transfer process (TRL6). The latter is not yet fully automated. ANL’s Delft foundry location with access to the facilities of the TU Delft EKL Laboratory and world class material scientists enable ANL to propose an innovative industrial foundry service for graphene. With the SPRING project, ANL aims to scale-up and automate its 2D material foundry technology, bringing it to the commercialisation stage (TRL9). Within 5 years from the project ending, ANL expects to obtain revenues of €54m and an EBIT of nearly €9m. ANL’s mission is to be the leading global foundry for integrating 2D materials in the designated markets.
In this first review period, the work has concentrated on the automation and the production of the first electrical device wafers which brings the most improvement in the whole process flow. High temperature robot handling has been added to the CVD tool, which enables a significant speedup and allows full automated batch operation. Also, ANL’s unique 2D delamination process has been further automated.
To enable high volume production, it is essential to closely monitor the quality of each process step. Therefore, automation has been added to the optical inspection equipment as well as real-time software analysis to automatically determine the graphene coverage across the wafer. Also, the Raman spectroscopy equipment has been automated and software has been improved to automatically determine the Raman parameters on many points across the wafer for multiple wafers at once. Optical and Raman inspection will be executed on every wafer and at three different steps in the whole process flow to closely monitor the quality of the process.
Optical and Raman inspection are well suited to keep the process under control, but it is also important to regularly verify the electrical parameters of the graphene, when transferred to different substrates. Therefore, a process control monitoring chip (PCM) has been designed with electrical contacts and a variety of PCM structures to determine the electrical parameters of the transferred graphene.
To enable high volume production, it is essential to closely monitor the quality of each process step. Therefore, automation has been added to the optical inspection equipment as well as real-time software analysis to automatically determine the graphene coverage across the wafer. Also, the Raman spectroscopy equipment has been automated and software has been improved to automatically determine the Raman parameters on many points across the wafer for multiple wafers at once. Optical and Raman inspection will be executed on every wafer and at three different steps in the whole process flow to closely monitor the quality of the process.
Optical and Raman inspection are well suited to keep the process under control, but it is also important to regularly verify the electrical parameters of the graphene, when transferred to different substrates. Therefore, a process control monitoring chip (PCM) has been designed with electrical contacts and a variety of PCM structures to determine the electrical parameters of the transferred graphene.
ANL process flow differs from the standard SoTA CVD graphene process flow. Instead of using a copper foil as growth substrate, a semiconductor wafer is used. This results in a flatter growth surface and a higher quality graphene with less wrinkles. Furthermore, ANL’s unique 2D delamination process enables re-use of the semiconductor wafer and does not require any aggressive chemical process to dissolve the copper foil. To transfer the graphene wafer to a semiconductor wafer, it is not scooped out of water, but an industry standard wafer bonder is used to do this.
The whole process flow is optimized to enable wafer to wafer transfer of graphene within standard semiconductor process flows and high-volume semiconductor production lines. To achieve this, ANL also developed high-throughput optical and Raman monitoring equipment.
The whole process flow is optimized to enable wafer to wafer transfer of graphene within standard semiconductor process flows and high-volume semiconductor production lines. To achieve this, ANL also developed high-throughput optical and Raman monitoring equipment.