1x stencil masks fabrication and their use in Low-Energy Electron-beam Proximity Lithography (LEEPL)

摘要

Thirty years ago it was the common believe of most of the lithographer that the limit end for the optical lithography will be at about 1 μm ground rule. So NGL tools were developed to go in the 500nm and 250nm regions. 15 years later the different optical lithography techniques were still alive exposing feature sizes down to 200nm and the NGL tool developer had to move to 100nm and below. Today 100nm features made by optical lithography is world wide a common technique in most of the modern chip manufacturing plants, and feature sizes beyond the used wavelength are state of art. So do we really need NGL or will the optical lithography lives forever? Well, there are already optical system available or will be soon delivered to the manufacturing lines which are able to expose feature sizes down to 70nm and even to 50nm if they use 193nm immersion lithography. But for what price? The optical lithography became extremely expensive. Reticles for the 70nm technology full with OPC structures may cost up to