High Temperature Spin on Carbon Materials with Excellent Planarization and Chemical Vapor Deposition Compatibility

摘要

The use of multilayer processes in advanced ArF patterning schemes continues to increase as device criticaldimensions shrink. In a multilayer stack, underlayer materials play a critical role in terms of gap fill, planarization andetch resistance to enable high resolution and high aspect ratio patterning. The emerging quadlayer imaging process requiresa unique spin on carbon (SOC) layer with high thermal stability to withstand subsequent deposition of an inorganic hardmask layer, commonly deposited via chemical vapor deposition (CVD). The thermal stability requirement associated withCVD compatibility largely limits the options of organic materials, which mostly decompose in the 300-450°C range.Thermal shrinkage and coefficient of thermal expansion (CTE) differences between layers are other key considerations indesigning a high temperature stable, CVD compatible SOC material. Furthermore, the SOC polymer resin must becompatible with solvents and spin on products commonly used in the FAB. This paper highlights the development of anovel CVD compatible HT-SOC platform with excellent thermal stability (>500°C) and good FAB drain linecompatibility. In addition, this polyaromatic SOC platform shows various improvements compared to traditional NovolacbasedSOC, including reduced shrinkage, good gap fill, improved planarization, and low defectivity. Robust formulationdesign, high quality raw materials, and advanced metal removal technique synergistically enabled manufacturing of multigallonHT-SOC product with high quality. Application specific versions are available for more demanding planarizationrequirement and applications that require good adhesion to metal substrate. In addition, a newly developed method forquantitative measurement of long-range planarization was used to validate new material designs aimed at improvingplanarization.