Application.1_ORGANIC POLYMER PHOTOLITHOGRAPHY

  • AUTHOR: 172NM
  • 2019뀈 11쐢 9씪
Application.1_ORGANIC POLYMER PHOTOLITHOGRAPHY

Application
1. ORGANIC POLYMER PHOTOLITHOGRAPHY

Optical micrograph of acrylic sheet exposed through a photomask for 90 s. Numbers on top represent feature size in 關m

The -Cygni eliminates the need for specific resist chemistries – because of the high-energy of the light (7.2eV per photon), practically any organic polymer can now be utilized as a photoresist! 2-CYGNI셲 172nm allows for higher resolution imaging, the use of simple and inexpensive resists, and the elimination of alkali waste generated by traditional DNQ-based resist systems.

New Resists, New Possibilities
Rethink traditional photoresists. Because of the nature of the exposure mechanism, a photosensitizer is no longer needed. Simply put, the 2-CYGNI breaks down organic polymer chains until they become volatile and evaporate – there is mass reduction of the exposed polymer. This process is universal – practically all organic polymers can now be used as a photoresist, even in bulk form.

Dry/Positive/Negative Processing – You Decide!
The image is generated during the exposure due to the mass reduction of the organic film, thus eliminating the need for a separate developing step. The resulting height contrast is sufficient for some processes, reducing process time and waste generation.
To meet more demanding applications, the organic polymer may be further processed after exposure to increase resolution. However, unlike traditional resists, the tone (positive or negative) is determined by the developing solution, not a sensitizer. In addition to mass reduction and evaporation, cross-linking occurs in the polymer during exposure as the chain length is reduced. This cross-linking changes the solubility of the polymer in specific solvents – alcohol-based developing solutions generate positive-tone images, while acetone and similar solvents generate negative-tone images.

SEM image of 200 nm thick PMMA photoresist on Si substrate exposed through a photomask for 40 s. Numbers on top represent feature size in 關m