TROM2 chip: A chip for mask production

The semiconductor industry has been striving for decades to optimize the energy consumption, switching speed and area requirements of electronic components through miniaturization. After more than 50 years of continuous miniaturization of structures, the greatest technical and physical barriers currently lie in the imaging technologies of photolithography and here specifically in the production of high-resolution photomasks. Photomasks are needed in every chip fabrication to transfer the micro- to nanometer-sized structures that define the chip onto a photoresist-coated silicon wafer. 

A technology node (smallest structure size) defines an achievable miniaturization level and thus the manufacturing processes based on it. By falling below the 10 nm technology node a few years ago, EUV lithography with a wavelength of only 13.5 nm became indispensable for further technical development.  

For the fabrication of photolithographic EUV masks, techniques are needed that allow the definition of very small structures sufficiently fast and efficiently. So-called electron beam mask writers are used for this purpose. 

If EUV masks with a high density of complex geometric structures are to be written, the current single-beam electron mask writers reach their limits. Limiting factors here are both the large amounts of data required to define such masks and the writing time required to produce them on the mask substrate. Single-beam electron mask recorders, for example, would require several days of writing time for a complex EUV mask.