Dry development rinse (DDR) process and material for ArF/EUV extension technique toward 1Xnm hp and beyond

Abstract

Since the pattern pitch is getting smaller and smaller, the pattern collapse issue has been getting sever problem in the lithography process. Pattern collapse is one of the main reasons for minimizing of process margin at fine pitch by ArF-immersion or EUV lithography. The possible major cause of pattern collapse is the surface tension of the rinsing liquid and the shrinkage of resist pattern’s surface. These surface tension or shrinkage are occurred in the spin drying process of the rinsing liquid. The influence of surface tension against very small pitch pattern is particularly severe. One of the most effective solution for this problem is thinning of the resist film thickness, however this strategy is reaching to its limits in terms of substrate etching process anymore. Recently the tri-layer resist process or hard mask processes have been used, but there is a limit to the thinning of resist film and there is no essential solution for this problem. On the other hand, dry development process such a supercritical drying method or DSA patterning by dry etching have been known as an ultimate way to suppress the pattern collapse issue. However, these processes are not applied to the mass production process right now because these have some problems such a defect issue, requirement of the special equipment and so on. We newly developed the novel process and material which can prevent the pattern collapse issue perfectly without using any special equipment. The process is Dry Development Rinse process (DDR process), and the material used in the process is Dry Development Rinse material (DDR material). DDR material is containing the special polymer which can replace the exposed and developed part. And finally, the resist pattern is developed by dry etching process without any pattern collapse issue. In this paper, we will discuss the approach for preventing the pattern collapse issue in ArF and EUV lithography process, and propose DDR process and DDR material as the solution.