Patent Number: 6,251,791

Title: Eliminating etching microloading effect by in situ deposition and etching

Abstract: A method for eliminating the etching microloading effect is proposed for the invention. Spirit of the invention is that a coating layer is formed on a photo-resist that covers a substrate before the substrate is etched, where coating layer maybe a polymer layer or a dielectric layer. Because step coverage of the coating layer is limited by the aspect of trench, for photo-resist it means the width of openings, it is indisputable that depth of coating layer on bottom of a narrow opening is smaller than depth of coating layer on bottom of a wide opening. Therefore, during following etching process, although etching microloading effect induces etching rate is higher in the wide opening and is lower in the narrow opening, but the thicker coating layer on bottom of the wide opening also requires larger etching time than the narrow opening. Consequently, it is crystal-clear that the etching microloading effect is cancelled and then depth of the wide trench is equal to depth of the narrow trench.

Inventors: Tsai; Ming-Huan (Chu-Pei, TW), Yang; Chan-Lon (Taipei, TW)

Assignee: United Microelectronics Corp.

International Classification: H01L 21/02 (20060101); H01L 21/311 (20060101); H01L 021/311 ()

Expiration Date: 06/26/2018