Lithography
What effect is expected when directed self-assembly (DSA) is combined with EUV lithography?
- AEUV masks become unnecessary
- BResist sensitivity rises so that EUV source power is no longer needed
- CUsing EUV patterns as guides, the pattern is snapped to a regular period, reducing line-width and roughness variation caused by stochastic effects
Show answer and explanation
Answer: C. Using EUV patterns as guides, the pattern is snapped to a regular period, reducing line-width and roughness variation caused by stochastic effects
In EUV lithography, few photons are used per exposure, so stochastic effects cause variation in line width and line-edge roughness. In directed self-assembly (DSA), the period of the block copolymer pattern is fixed by the material, so self-assembling on EUV-made guide patterns is expected to smooth out that variation. imec, Intel and others have reported results since the early 2020s, but reducing defects to extremely low levels is the challenge for volume production.
- A. The guide patterns are made by EUV exposure, so masks are still needed.
- B. DSA does not solve resist sensitivity or source power problems.
- C. Correct. This is the rectification use of DSA.