Photoresist underlayer and method of manufacturing a semiconductor device

A photoresist underlayer composition, comprising:

• a first polymer comprising pendant acid-labile groups including one or more structures selected from
• a second polymer having one or more crosslinking groups;
• an acid generator;
• greater than 0 wt. % to 10 wt. % of a quencher or a photodecomposable base based on a total weight of the first and second polymers;
• and
• a solvent,
• wherein the quencher is one or more of
• and the photodecomposable base is one or more compounds comprising a combination of an anion and a cation selected from:

A photoresist underlayer composition, comprising:

• a first polymer comprising pendant acid-labile groups including one or more structures selected from
• a second polymer having one or more crosslinking groups;
• an acid generator;
• 0.1 wt. % to 10 wt. % of a photodecomposable base based on a total weight of the first and second polymers;
• and
• a solvent,
• wherein the crosslinking groups are one or more of
• wherein R1 is a connecting group selected from —S—, —P—, —P(O2)—, —C(═O)S—, —C(═O)O—, —O—, —N—, —C(═O)N—, —SO2O—, —SO2S—, —SO—, —SO2—, a carboxylic acid group, ether group, ketone group, ester group, 1-9 carbon aliphatic groups or aromatic groups, wherein the aliphatic or aromatic groups are unbranched, branched, cyclic, noncyclic, unsubstituted, or substituted with one or more halogens.