ABSTACT 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 plananzing 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 O.2Oim 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 O.2Oim indicated that there was good compatibility of the BARCs with the resists. The thin film etching selectivity to commercial resists was about I .2: 1 under an HBr/02 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.

There are an increasing number of applications in the microelectronics industry that require materials that can fill and planarize high-aspect ratio topography. These applications call for the formation of a flat coating surface without the use of high bake temperatures or high-pressure processes. Potential device markets include MEMS, 3D-ICs, LEDs, semiconductors, flat panel displays and related microelectronic and optoelectronic devices. Various polymeric coating materials have been developed that have intrinsic self-leveling properties and are able to fill deep trenches and holes found on microelectronic substrates without forming voids. These new materials are able to reflow at modest baking temperatures (50–100 °C) and can fill high-aspect ratio features (10:1) by spin coating single or multiple layers of material over the topography. Several of these polymeric materials remain soluble in TMAH (and other aqueous bases), some are photosensitive, and all materials are compatible with industry-accepted solvents. Results from extended process development work on self-leveling polymeric materials will be discussed and comparisons made to industry-accepted practices.

The primary benefits of bottom anti-reflective coating (BARC) in photolithography are focus/exposure latitude improvement, enhanced CD control and the elimination of reflective notching. As the semiconductor industry demands higher chip functionality, the drive to reduce linewidths and increase die density per wafer is intense. The introduction of BARC technology can postpone the necessity to introduce new equipment needed for these shrinks by enhancing the capability of existing equipment , thus reducing product development time and also eliminating qualification of new material and tool sets. This paper reviews substrate reflectivity, and discusses and reports on material requirements for advanced organic BARCs. Some of the new BARC products based on the design requirement will also be discussed.

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