Advanced STI patterning for 70 nm DRAM technology and beyond

Abstract

This paper presents the resufb on the patterning of shalfow french isolation for the 70nm DRAM technology node on 300mm wafers. Using a new friple hard mask approach incorporating a carbon plm patterns with 70nm CD and STI depth of abaut 250nm could be achieved. Keywords

Inductively Coupled Plasma Etching of Chemical-Vapor-Deposited Amorphous Carbon in N2/O2/Ar Chemistries

“…Recently, an MLR structure having an amorphous carbon (a-C) mask layer deposited by chemical vapor deposition (CVD) has been used. 1,2) CVD a-C has several potential applications, particularly in the microelectronics industry, because of its optical, electrical and mechanical properties. [3][4][5][6] Such a-C films can be obtained by several techniques, such as laser evaporation, ion beam and plasma deposition.…”

“…Furthermore, only a few reports on the etch characteristics of a-C layers for MLR have been published. 1,2,6,12) In this work, a CVD a-C thin film layer, synthesized by RF plasma enhanced CVD (PECVD) method with methane (CH 4 ) and hydrogen (H 2 ) gases, was etched and its etch characteristics and the etch mechanism of the CVD a-C films were investigated using O 2 /N 2 /Ar inductively coupled plasmas (ICPs) at various gas flow ratios and plasma powers. Experimental results indicated that the etch rate and profile angle were decreased with increasing N 2 flow rate due to the increased formation of CN x phase on the a-C surface.…”

Ultrahigh Selective Etching of SiO[sub 2] Using an Amorphous Carbon Mask in Dual-Frequency Capacitively Coupled C[sub 4]F[sub 8]/CH[sub 2]F[sub 2]/O[sub 2]/Ar Plasmas

“…Due to the difficulties in directly etching the underlayer using an ArF PR mask, new schemes have been developed for nanoscale patterning, such as using multilayer resist ͑MLR͒ structures. [1][2][3] An MLR structure is typically composed of a SiO x or SiON hard mask, an amorphous carbon layer ͑ACL͒, and Si 3 N 4 or SiO 2 underlayers. The final Si 3 N 4 or SiO 2 underlayers are patterned with an etched ACL pattern.…”