TrueMask, a purpose-built supercomputer, developed to enable stitchless, full-chip ILT in single day

D2S claims TrueMask could enable semiconductor fabs to create more advanced chips without having to upgrade equipment

Semiconductor company Design-2-Silicon (D2S) has claimed that a breakthrough in inverse lithography technology (ILT) could speed-up the process of chip-making, and enable semiconductor fabs to produce more advanced chips without having to upgrade their equipment.

The San Jose, California-based company has developed a custom-built system that can compute an entire stitchless, full-chip ILT solution for advanced node design in a day. They claims that it could reduce the amount of time required to perform a critical step in chip making from several weeks to just a single day.

The new system could also enable semiconductor fabs to design and create more advanced chips without having to purchase new equipment.

The new system, dubbed TrueMask, is a GPU-accelerated hardware and software system, in which each component has been optimised for inverse lithography technology (ILT).

ILT is a highly complex computational technique used to determine the optimal mask patterns in order to print a desired pattern on wafers. Researchers say that this technique is useful in producing good results in terms of resilience to manufacturing variation.

However, some issues with ILT have restricted its wider use in the industry for the past decade.

Specifically, long run-times due to a large number of computations (needed to perform full-chip ILT) had been a major hindrance, unresolved until now.

With TrueMask, the researchers expect this hurdle to be finally solved forever.

"Wafer fabs need to deliver wafers in the shortest time possible, which requires ILT process time to be shrunk to a single day in order to be practical," said Leo Pang, executive vice president at D2S.

TrueMask is the "the first commercial ILT solution" that promises to deliver full-chip ILT within that time constraint.

The software developed for TrueMask combines many GPUs and CPUs in such a way that they act like a virtual, gigantic GPU, which can handle the entire chip at a time.

To test the performance of the system, researchers created photomasks for the process layers that required the most rigorous tolerances.

The patterns produced by TrueMask on wafer exhibited a greater than 100 per cent improved tolerance to variations in dosage and focus than that of current optical proximity correction technology, used in the industry today.

These results should mean that chipmakers won't need to buy new photolithography machines to move to a more advanced manufacturing node. In addition, the new system could also help reduce the process cost by eliminating the need for one or more photomasks.

The detailed findings of the research were discussed last week at the SPIE Photomask Technology and EUV Lithography Conference.