Method for structuring a photoresist layer

A process for structuring a photoresist layer, which comprises:

• a) providing a substrate to which a photoresist layer is applied at least in some areas, the photoresist layer including:
• a film-forming polymer containing molecular groups convertable into alkali-soluble groups by acid-catalyzed cleavage reactions;
• a photoacid generator releasing an acid on exposure to light in a first defined wavelength range (Δλ1);
• and
• a photobase generator releasing a base on exposure to light in a second defined wavelength range (Δλ2);
• b) exposing areas of the photoresist layer to a first light in the second defined wavelength range (Δλ2), the first light having a wavelength at which the photoacid generator is substantially inert;
• c) exposing areas of the photoresist layer to a second light in the first defined wavelength range (Δλ1), the second light having a wavelength at which the photobase generator is substantially inert;
• d) heating the photoresist layer to a temperature at which the acid-catalyzed cleavage reaction occurs;
• and
• e) developing the photoresist layer.