Photoresist

A lithography method, comprising:

• forming a target layer over a substrate;
• applying a photoresist composition over the target layer to form a photoresist layer, wherein the photoresist composition comprises:
• a polymer;
• a photo acid generator (PAG) sensitive to extreme ultraviolet (EUV) radiation;
• a radical quencher comprises:
• a core containing C3 to C80 saturated or unsaturated hydrocarbon ring or C2 to C80 heterocyclic saturated or unsaturated hydrocarbon;
• and
• a group connected to the core as a substituent, wherein the group comprises a bond dissociation energy in a range from about 10 kcal/mol to about 1000 kcal/mol;
• and
• a solvent;
• exposing the photoresist layer;
• developing the photoresist layer;
• and
• etching the target layer using the photoresist layer as an etch mask.

An extreme ultraviolet lithography (EUVL) method, comprising:

• turning on a droplet generator to eject a metal droplet toward a zone of excitation in front of a collector;
• turning on a laser source to emit a laser toward the zone of excitation, such that the metal droplet is heated by the laser to generate EUV radiation;
• guiding the EUV radiation, by using one or more first optics, toward a reflective mask in an exposure device;
• and
• guiding the EUV radiation, by using one or more second optics, reflected from the reflective mask toward a photoresist layer coated substrate in the exposure device,
• wherein the photoresist layer is formed by applying a photoresist composition comprising a polymer comprises a moiety comprising a radical quencher.