Production x-ray lithography stepper for 100-nm device fabrication

We have developed a new production of x-ray stepper for 100- nm device fabrication and beyond. In this paper, at first we introduced two techniques that are installed into our new stepper. The second, we reported a series of exposure results using the new stepper. First technique is a new method for gap setting, which we call direct gap setting (DGS) system. The DGS system is composed of a capacitive sensor and a reflective displacement laser sensor. Since this approach does not require any preexisting mark on the substrate, three channels of the DGS system automatically complete the gap setting with an accuracy of 1.5 micrometers in a measurement range of 10-50micrometers . Second technique is a scattered light alignment system (SLA), which is a video- based optical sensor. The digital signal processing of the SLA system calculates the relative displacement between mask mark and wafer mark. The stepper is installed in our Tanashi works for x-ray exposure test. In double exposure test using one x-ray mask, the stepper achieved an overlay accuracy (mean +/- 3(sigma) ) of -1 +/- 15nm for x-axis and 4 +/- 11nm for y-axis. The result demonstrates that PXL is a strong candidate for manufacturing as we approach 100-nm scale device replication and sub-100nm region.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.