G03F 1/32 - Definition

Definition statement

This subclass covers:

Subject matter of subgroup G03F 1/26 in which the phase shift mask (PSM) has an attenuating region that produces phase shifted exiting illumination at a different phase from that produced by a non-attenuating clear region of the attenuating PSM (e.g., PSM having semi-transparent phase shift portion, halftone PSM); and in which the process of preparing is directed to preparation of such an attenuating PSM (att-PSM).

(1) Note. In this attenuating PSM (att-PSM, halftone PSM), the attenuating or halftone region is partially transmissive and provides a phase shift (PS) in exiting illumination. The degree of PS and the transmissiveness of the att-PS region depends on the material and thickness of the att-PS region, as well as depending on the wavelength of the illumination. Such an att-PS region or a halftone PS region can be formed by adding an appropriate material at a suitable thickness, reducing the thickness of a previously formed layer (whether a supporting substrate of the att-PSM or an additional layer thereon), or other post-treatment of an att-PSM portion (such as selective doping or ion implantation).

(2) Note. An att-PS region can be created by sufficiently reducing the thickness of a normally opaque absorber layer material, such as a thin layer of chromium (Cr) often called "leaky chrome".