US 10,303,056 B2  72  71  -continued  PAGl  PAG2  PAG3  PAG4  3) Preparation of Resist Compositions  4) EUV Exposure Test  Examples 1 to 8 and Comparative Examples 1 and  2  Positive resist compositions were prepared by dissolving  selected components in a solvent in accordance with the  recipe shown in Table 1, and filtering through a filter having  a pore size of 0.2 µm. The solvent contained 100 ppm of a  surfactant FC-4430 (3M).  The components in Table 1 are as identified below.  Polymers 1 to 5: polymers synthesized in Synthesis  Examples 2 to 6  Comparative Polymers 1 and 2: polymers synthesized in  Comparative Synthesis Examples 1 and 2  Organic solvents: propylene glycol monomethyl ether  acetate (PGMEA) propylene glycol monomethyl ether  (PGME) cyclohexanone (CyH) diacetone alcohol (DAA)  Acid generators: PAGl to PAG4 of the following structural  formulae  Basic compound: Quencher 1 of the following structural  formula  The positive resist composition was spin coated on a  silicon substrate having a silicon-containing spin-on hard  mask SHB-A940 (Si content 43 wt  %) coating of 20 nm  thick and pre baked on a hot plate at 105°  C. for 60 seconds  to form a resist film of 60 am thick. Using an EUV scanner  NXE3300 (ASML, NA 0.33, o0.9/0.6, quadrupole illumi› nation), the resist film was exposed to EUV through a mask  bearing a hole pattern at a pitch 46 nm (on-wafer size) and  0  0  ~  0  r  0  0  F2  0  C  Y’s03- 0  CF3  9  ~s~  V  Mw~7,300  Mw/Mn~ 1.88  0 ))  O  0~ 0 ~s03- F F  0  Q  CCO +  #  0  Quencher 1 