Slater & Matsil, L.L.P.
Method of forming planarized coatings on contact hole patterns of various duty ratios
A method of forming a planarized photoresist coating on a substrate having holes with different duty ratios is described. A first photoresist preferably comprised of a Novolac resin and a diazonaphthoquinone photoactive compound is coated on a substrate and baked at or slightly above its Tg so that it reflows and fills the holes. The photoresist is exposed without a mask at a dose that allows the developer to thin the photoresist to a recessed depth within the holes. After the photoresist is hardened with a 250° C. bake, a second photoresist is coated on the substrate to form a planarized film with a thickness variation of less than 50 Angstroms between low and high duty ratio hole regions. One application is where the second photoresist is used to form a trench pattern in a via first dual damascene method. Secondly, the method is useful in fabricating MIM capacitors.
Taiwan Semiconductor Manufacturing Company
Chia-Shiung Ching-Sen Feng-Jia Gwo-Yuh Shih-Chi Chia-Tung Jieh-Jang
Tsai Kuo Shih Shiau Fu Ho Chen