Novel technology of high-aspect-ratio etch utilizing coverage-controllable atomic layer deposition

Abstract

We demonstrated a coverage-controllable sidewall protective film by controlling the degree of oxidation during plasma-enhanced SiO2 atomic layer deposition (ALD) as a novel technology to suppress bowing in a high-aspect-ratio-contact (HARC) hole etch process. By depositing SiO2 protective film with atomic order on only the top-local region of patterns, to suppress bowing was achieved during HARC etch without the shrinkage of the bottom critical dimension (CD) and etch-stop. In addition, we investigated the parameters that determine the ALD coverage to estimate the coverage profile of sidewall protective film. By analyzing the relationship between activation time and ALD film thickness at each AR, we confirmed that the coverage is determined by the transport of oxygen radical based on the Knudsen transport model. Furthermore, we developed an ALD simulator from the transport model, and successfully estimated the coverage of protective film during etching to improve the verticality of the HARC profile with small bowing-bottom CD bias.

Modeling and simulation of coverage and film properties in deposition process on large-scale pattern using statistical ensemble method

“…Such a large-scale evolution of the deposition profile and film properties was predicted within a short calculation time considering the effect of the pre-process, such as plasma etching. In addition, an etch/depo/etch sequential process for the HAR pattern 5) can be simulated.…”

“…1) Moreover, advanced complex structures and vertical integration, including fin-type field-effect transistors (FinFET), 2) vertical tunnel FETs, 3) and gate-all-around FETs, 4) have been proposed. Therefore, careful deposition process control [5][6][7][8][9][10][11][12][13][14][15][16][17] for the realization of a high-aspect-ratio (HAR) pattern to consider the coverage and film properties (density, passivation, adhesion, etc. ), both of which greatly affect the device performance, is vital.…”

Progress report on high aspect ratio patterning for memory devices

“…In addition, polymer buildup on the mask and profile can lead to striation of the profile sidewalls due to uneven polymer build-up under the subsequent high-power HAR etch step. 24) Recently, Kumakura et al 27) reported applying coverage-controlled atomic layer deposition (ALD) silicon oxide film to reduce the profile bowing in HAR contact hole etching. While the use of ALD SiO 2 film to protect sidewalls is effective in some process regions, the low selectivity of sidewall passivation to the dielectric film may present some limitations in HAR ONON channel hole applications.…”

Characterizing catalyst function and transformations in the plasma reduction of CO2 on atomic layer deposition-synthesized catalysts

“…32,33 This control, along with the low-pressure deposition environment, allows for the coating of high aspect ratio or geometrically complex features, such as microwires or foams, without the line of sight restrictions imposed by other coating techniques such as sputtering or flamespray. [34][35][36][37] ALD has been used to synthesize electrocatalysts or thermal catalysts on supports for CO 2 reduction. 38,39 With respect to plasma catalysis, ALD has primarily been used as a method for applying catalysts developed for pollutant degradation and non-oxidative methane coupling.…”