Lithography

What is the main purpose of treating the wafer surface with HMDS or similar before coating resist?

  1. ATo make the surface hydrophobic, improving resist adhesion and preventing lifting during development
  2. BTo increase resist sensitivity
  3. CTo make the surface conductive
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Answer: A. To make the surface hydrophobic, improving resist adhesion and preventing lifting during development

Oxide surfaces readily adsorb moisture, and resist does not adhere well to them as is. Treating with HMDS (hexamethyldisilazane) makes the surface hydrophobic, improving resist adhesion and preventing patterns from peeling during development.

  • A. Correct. It makes the surface hydrophobic to improve adhesion.
  • B. It does not change resist sensitivity.
  • C. It is not a treatment for making the surface conductive.
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