Development of Full-fill Bottom Anti-reflective Coatings for Dual Damascene Process


Houlihan, F. M.


Among the variety of dual damascene (DD) processes, the via-first approach has drawn much attention because of its reduced process steps and improved photolithography process window. The via-first process requires a layer of via-fill material to be applied beneath the photoresist layer. The primary function of this via-fill material is to act as an etch-block at the base of the vias to prevent over-etching and punch-through of the bottom barrier layer during the trench-etch process. However, such materials also help to planarize the substrate and may limit back reflection from the substrate as well, helping to control the critical dimension (CD) of the printed features. Based on this understanding, our research efforts have been focused on the advancement of DD-applicable bottom antireflective coatings (BARCs). A series of novel planarizing DUV BARCs with full-via-fill properties and enhanced etching selectivity to resists have been developed. They showed good full-fill, void-free performance in 0.20μm vias having an aspect ratio of five(5), also sufficient top coverage i.e., enough coating thickness, low surface variation, and little thickness bias of isolated-via (1:10) area versus dense-via (1:1) area. The resist sidewall profiles with feature sizes less than 0.20μm indicated that there was good compatibility of the BARCs with the resists. The thin film etching selectivity to commercial resists was about 1.2:1 under an HBr/O2 atmosphere. A study of the BARCs described in this report allows further discussion of the impact of pattern density, feature size, and processing conditions on BARC coating performance.

Meeting Name

Proceedings of SPIE - The International Society for Optical Engineering (2001, Santa Clara, CA)



Document Type

Article - Conference proceedings

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© 2001 SPIE -- The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Jan 2001