MASKS FOR LASER-ABLATION TECHNOLOGY - NEW REQUIREMENTS AND CHALLENGES

Laser ablation is used as a dry patterning process in which an intense beam of light from an excimer laser is used to pattern a material dir ectly, This process has found extensive application in the microelectr onics industry for patterning of polymer materials, A typical laser ab lation tool is very similar to a conventional optical lithography proj ection tool; the primary difference is the wavelength and the intensit y of the light used in the ablation process, Conventional chromium-coa ted quartz masks are incompatible with Ix laser ablation tools because the chromium layer is rapidly damaged, This paper discusses a mask te chnology which has been developed specifically for excimer laser ablat ion, The mask consists of a quartz substrate with a stack of dielectri c films which have been selected for the laser ablation wavelength, Ma sk fabrication is accomplished with standard microelectronic processes and equipment, Such masks have been used in IBM manufacturing since 1 987 and have met all process specifications such as resolution, defect density, and damage resistance.