Sub-45 nm SiO₂ Etching with Stacked-Mask Process Using High-Bias-Frequency Dual-Frequency-Superimposed RF Capacitively Coupled Plasma

Abstract

By using a stacked mask process (S-MAP) with spun-on-carbon (SOC) film, 38 nm line patterns were successfully etched by controlling the ion energy using high-bias-frequency dual-frequency-superimposed (DFS) rf capacitively coupled plasma in combination with the low hydrogen content SOC film. It was found that ions with higher energy enhance the fluorination of SOC and induce pattern wiggling under fluorine exposure. By using a higher bias frequency to control the ion energy distribution and reduce the maximum ion energy, the SOC pattern wiggling was effectively suppressed.

Selective etch of poly(methyl methacrylate) in block copolymer based on control of ion energy and design of gas chemistry for directed self assembly lithography

“…A 100/13 MHz dual frequency superimposed capacitively coupled plasma (DFS-CCP) was used in this study. 20) The plasma process conditions were fixed at a 100 MHz power of 700 W, a pressure of 1.33 Pa, a substrate temperature of 40 °C, and a total gas flow rate of 300 sccm.…”

Improvement of the plasma‐induced defect generation model in Si substrates and the optimization design framework

“…[28,29,41,42,44] In the conventional PPD range theory, [33] IEDF is included to predict the depth profile of incident species n ion and the creation of defects (n dam ) because E ion is not monochromatic due to an applied RF bias. [45][46][47][48][49] The conventional PPD range theory gives plausible explanations for experimental results such as the E ion dependence of d dam assessments and the effects of the IEDF on d dam . It was suggested that d dam is a weak function of the bias frequency.…”

“…Note that the profile of injected ions around the depth R p can be widely approximated as a Gaussian distribution with a standard deviation called the projected straggle σ p . In the conventional PPD range theory, IEDF is included to predict the depth profile of incident species n ion and the creation of defects ( n dam ) because E ion is not monochromatic due to an applied RF bias . The conventional PPD range theory gives plausible explanations for experimental results such as the E ion dependence of d dam assessments and the effects of the IEDF on d dam .…”

Review of methods for the mitigation of plasma‐induced damage to low‐dielectric‐constant interlayer dielectrics used for semiconductor logic device interconnects

“…The SOG mask controls the etching amount of the bottom resists in via holes . To achieve the better‐patterned shape, a tri‐layer consisting of a top layer of thin resist for patterning, a SOG interlayer, and a spun‐on carbon (SOC) film bottom layer was introduced in DD schemes, called a stacked mask process (S‐MAP) . The SOC film has high carbon content and low‐oxygen content, and exhibits higher etching resistivity than that of conventional resist films.…”

“…[12][13][14] To achieve the better-patterned shape, a tri-layer consisting of a top layer of thin resist for patterning, a SOG interlayer, and a spun-on carbon (SOC) film bottom layer was introduced in DD schemes, called a stacked mask process (S-MAP). [15][16][17][18] The SOC film has high carbon content and low-oxygen content, and exhibits higher etching resistivity than that of conventional resist films. Via-first DD formation with S-MAP eliminates the undesirable SiO 2 fence around the top of via holes.…”