Humidity Induced Defect Generation and Its Control during Organic Bottom Anti-reflective Coating in the Photo Lithography Process of Semiconductors

Abstract

Defect generation during organic bottom anti-reflective coating (BARC) in the photo lithography process is closely related to humidity control in the BARC coating unit. Defects are related to the water component due to the humidity and act as a blocking material for the etching process, resulting in an extreme pattern bridging in the subsequent BARC etching process of the poly etch step. In this paper, the lower limit for the humidity that should be stringently controlled for to prevent defect generation during BARC coating is proposed. Various images of defects are inspected using various inspection tools utilizing optical and electron beams. The mechanism for defect generation only in the specific BARC coating step is analyzed and explained. The BARC defect-induced gate pattern bridging mechanism in the lithography process is also well explained in this paper.

Review—Airborne Molecular Contamination: Recent Developments in the Understanding and Minimization for Advanced Semiconductor Device Manufacturing

“…29 During the photolithography process, water molecules can react with hydrophilic, organic bottom anti-reflective coating (BARC) after coating (before baking), causing pattern bridging by altering the uniformity of the BARC etching process. 30 In the back-end-of-line (BEOL) process, moisture was found to be a catalyst forming a non-conductive Al-F-O layer in the via hole bottom between Ti/TiN and W plug, causing high via resistance. More recently, water molecules were also deemed detrimental to the optoelectronic properties of III-V semiconductor material for thin-film transistors.…”