4-(4-(tert-Butyl)phenyl)-1,4-oxathian-4-ium 1,1-difluoro-2-oxo-2-((5',5',6',6'-tetrafluorospiro[adamantane-2,2'-[1,3]dioxepan]-5-yl)oxy)ethane-1-sulfonate
CAS 1371590-55-4
In advanced photoresists, even the counterion is engineered. PAG554 shows why controlling acid diffusion can matter as much as generating the acid itself.
PAG554 (CAS 1371590-55-4) shows how far photoacid-generator design has evolved. Its oxathianium cation is paired with a bulky fluorinated, spiro-adamantane sulfonate anion. In chemically amplified photoresists, generating strong acid is only half the problem: acid mobility must also be controlled. At nanometer dimensions, counterion structure can influence diffusion, compatibility and image blur.
Published:
2026-09-17
![4-(4-(tert-Butyl)phenyl)-1,4-oxathian-4-ium 1,1-difluoro-2-oxo-2-((5',5',6',6'-tetrafluorospiro[adamantane-2,2'-[1,3]dioxepan]-5-yl)oxy)ethane-1-sulfonate](/structures/1371590-55-4.png)