Fundamental study of silylation for application to sub-0.35 micron lithography.

摘要

During the last decade the rapid demand for more dense ULSI devices has driven optical lithography down to the half micron regime (16 Mbit DRAM generation). Sub-half micrometer lithography using wet developable resist systems exhibits inherent problems such as: limited resolution and depth of focus, linewidth variations due to interference effects and multiple reflections over highly reflective topography.; In chapter I the conventional wet develop lithography problems are discussed. Advanced lithography techniques have been proposed as a solution to overcome inherent problems with conventional wet develop lithography. The DESIRE process has been suggested as an attractive solutions not only to improve resolution and process latitudes but also to cope with C.D. variations over topography.; In chapter II a fundamental study of the DESIRE process is discussed. A thermal analysis of the DESIRE process and a characterization of the silylation are presented. Several analytical methods are compared. The mechanism and kinetics are discussed. In a last section of this chapter the oxidation of silylated resist after O{dollar}sb2{dollar} plasma and the thermal stability are discussed.; In chapter III alternative silylating agents for gas phase silylation are systematically investigated for application to the DESIRE process. The alternative silylating agents have been applied to DUV lithography. The combination of phase shifting masks with the DESIRE process at DUV exposure is discussed.; In chapter IV surface imaging and dry development for E-beam lithography is studied. A positive process using gas phase silylation of chemically amplified resist is presented.; In chapter V focuses on liquid phase silylation for the DESIRE process. A comparative study between gas and liquid phase silylation is presented. A possible mechanism for liquid phase silylation is suggested. The influence of partial coherence on the resolution and process latitudes using conventional transmission masks and phase shifting masks are discussed in detail.