New Development Method Eliminating the Loading and Micro-Loading Effect

摘要

In recent years, more precise pattern dimension control (CD control) on a photomask has been required than ever as finer-line of IC pattern progresses. In the case of the conventional development (spray-development, puddle-development), CD control is difficult due to loading and micro-loading effect. The "loading and micro-loading effect" refers to the differences of exposed area around the pattern. The low pattern density generates numerous dissolution products and decreases the concentration of developer. This phenomenon changes resist dissolution rate and causes difficulties in controlling the CD. To solve this problem, we have been developing a new type of developer, called "Proximity Gap Suction Development (PGSD)". Nozzle of PGSD has five slits; opening for supplying developer is in the center, two suction slits are on the both sides, and two slits for rinse are on the very end. The proximity gap is kept between the nozzle surface and resist during development. Contaminated developer is immediately sucked/removed and stable development can be achieved by the continuous dispense of fresh developer at high speed. Thus, a desired pattern size can be obtained without loading and micro loading effect. We reported the principle of PGSD at BACUS in 2002. In this thesis, we would like to report the following topics. 1. System overview of a machine, which we are currently developing 2. Effect of the PGSD on CD uniformity and the number of defects.