Papers by Keyword: EUV Lithography

Abstract: For EUV lithography, a reflective mask is essential because of use of the strong energy, wavelength of 13.5 nm. The EUV mask consists of multi-layered, multi-material structure and is susceptible to various contaminants. Since EUV lithography process should be used in a high vacuum environment, an electrostatic chuck (ESC) is used to fix or hold the EUV mask using electrostatic force. In general, in order to use ESC chuck, it needs a thin conductive layer (CrN layer) on the backside. However, the contact points of the electrostatic pin chuck can make exfoliation of conductive CrN layer producing CrN particles. If these particles are present on the backside of the mask, CD or DOF may be affected during EUV exposure. The 1 μm particle can leads to a gap radius of 42mm [4]. Moreover, these backside particles may travel to the front side. Therefore, backside cleaning should be performed to remove particles from the mask backside surface.

Abstract: Nanocomposite materials based on poly(p-hydroxystyrene-co-2-methyl-2-adamantyl methacrylate-co-methacrylisobutyl-POSS) were synthesized and evaluated as EUV chemically amplified resists. Incorporation of 2-methyl-2-adamantyl and POSS groups into the matrix polymer made it possible to improve the dry-etch resistance, and excellent lithographic performance was obtained. The well-defined 250 nm positive patterns were obtained using a KrF excimer laser scanner, and 100 nm elbow patterns using an EUV lithography tool. The dry-etch resistance of this resist for a CF4-based plasma was comparable to that of poly(p-hydroxystyrene).