Process Considerations for Organic Bottom Anti-Reflective Coating BARC Optimization for Front-End and Back-End-Of-Line Integration

摘要

Bottom anti-reflective coatings [BARC] are now routinely used in semiconductor manufacturing to enable advanced lithography on, and patterning of, reflective substrates. For successful implementation into IC manufacturing lines, large and robust process windows must be defined. This article will describe the processing and material characteristics of BARC with reference to three applications where the introduction of a BARC layer is becoming essential. These are (ⅰ) the definition of the initial critical layers, (ⅱ) the introduction of thin resist implant processes and (ⅲ) the integration of copper interconnect to Back-End-Of-Line [BEOL] metalization. As with advanced photoresist, the requirements for BARC material is also becoming more demanding. As photoresists become thinner, BARCs are also required to be thinner and have increased etch rate compared to the photoresist. In addition to process optimization, particular attention will be given to fast etch rate conformal BARCs for sub 0.13 μm KrF and ArF manufacturing. Also wet patterning processing, where the BARC open etch step is eliminated since the BARC patterning occurs simultaneously in the resist develop step. For BEOL, the BARC requirements can be different, as trench and via structures require total planarization. In addition etch block is also necessary. Each of these material and process steps will be described.