Lithography

Which technique uses computation to jointly optimize the illumination shape of the exposure tool and the mask pattern to improve resolution?

  1. ASMO (source mask optimization)
  2. BCMP
  3. CALD
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Answer: A. SMO (source mask optimization)

SMO (source mask optimization) jointly optimizes the tool's illumination shape (source distribution) and the mask pattern including OPC to widen the process window. Inverse lithography technology (ILT), which back-calculates freeform curvilinear mask shapes, has also come into use.

  • A. Correct. Illumination and mask are optimized together.
  • B. CMP is a planarizing polishing step.
  • C. ALD is a deposition technique that adds one atomic layer at a time.
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More Lithography questions

  1. In immersion lithography with very high numerical aperture (NA), why does light polarization need to be considered?
  2. What is the main cause of "flare", a problem in EUV lithography?
  3. In EUV masks, what is the phenomenon called in which the absorber pattern's thickness is not negligible compared with the wavelength, so obliquely incident light casts shadows and otherwise affects the image?
  4. What are the weak spots in a layout called, which lithography or process simulation predicts are prone to patterns bridging or breaking?
  5. Why has gas released from resist (outgassing) been a concern in EUV lithography?