EXCIMER-LASER ABLATION OF NOVEL TRIAZENE POLYMERS - INFLUENCE OF STRUCTURAL PARAMETERS ON THE ABLATION CHARACTERISTICS

Novel photopolymers based on the triazene chromophoric group have been developed. Structuring by XeCl excimer laser irradiation at 308 nm r esults in ablation craters with clean contours and sharp edges; diffra ction-limited resolution of almost-equal-to 0.4 mum is achieved. A pro minent feature of the triazene polymers is the complete absence of sol id debris around the edges of the ablation craters, which makes these materials attractive for applications in microelectronics. The depende nce of the ablated depth per pulse on laser fluence is investigated an d is related to the effective absorption coefficient and the quantum y ield of photochemical decompostion of the polymers insolution. Other p hysicochemical and thermomechanical parameters of the polymers appear to be less influential on the ablation characteristics. The high fluen ce limit d(max) of the etch rate per pulse is found in the range betwe en 2 and 3 mum for all investigated materials. On exposure to several high fluence laser pulses, an ejection of material has been observed f rom areas that are considerably larger than the incident laser beam. T his effect may be due to either an explosive event or the generation o f shock waves reflected at the sample substrate.