Azobisisobutyronitrile → Propylene glycol methyl ether acetate

Participants

Reaction Conditions

Reaction Steps

A monomer solution was prepared by placing 4800 g of methyl ethyl ketone (hereinafter inscribed as “MEK”) in a tank kept at a nitrogen atmosphere, and dissolving 2080 g of 5-acryloyloxy-2,6-norbornanecarbolactone (hereinafter inscribed as “NLA”) as a repeat unit (B) having a polar group for enhancing adhesion to a semiconductor substrate {hereinafter (B) on a head of the compounds in the examples has the same meaning as this} and 2480 g of 2-ethyl-2-adamantyl methacrylate (hereinafter inscribed as “EAM”) as a repeat unit (A) which is decomposed by an acid to become alkali soluble (hereinafter (A) on a head in the compounds in the examples has the same meaning as this). A polymerization initiator was prepared by placing 700 g of MEK and 80 g of azobisisobutyronitrile (hereinafter inscribed as “AIBN”) in another container kept at a nitrogen atmosphere and dissolving. Into a polymerization tank kept at the nitrogen atmosphere, 3500 g of MEK was put and the temperature was raised to 80° C. with stirring. Subsequently, the monomer solution and the polymerization initiator solution kept at the temperature of 25 to 30° C. were fed into the polymerization tank kept at 80° C. over 4 hours, respectively. After the completion of feed, the polymerized solution was matured for 2 hours with keeping the polymerization temperature at 80° C., then cooled to room temperature and taken out. Polymer was precipitated from the resulting polymerized solution by dropping in 70 kg of aqueous methanol and filtrated. The resultant wet cake was washed with 70 kg of methanol, filtrated subsequently dissolved in MEK again, and passed through a filter 40QSH supplied from Cuno Incorporated to remove a trace amount of metals. Then, the solvent was replaced by PGMEA with removing MEK by heating under reduced pressure to prepare PGMEA solution containing 15% polymer. The features of the resultant polymer, the content of high polymer and the evaluation results of storage stability of PGMEA solution are shown in Table 1.

Provenance & Evidence