Role of surface temperature in fluorocarbon plasma-surface interactions

Nelson, Caleb T.; Overzet, Lawrence; Goeckner, Matthew

doi:10.1116/1.4729445

Cited by 5 publications

(2 citation statements)

References 21 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A thick FC layer usually acts an "inhibitor" or even a "stopper", if too thick, for etching; meanwhile, it also plays the role of etchant supplier when the F can be released from FC molecules under ion bombardment. Accordingly, the structures and thickness of the FC layers are amenable to the nature of plasmas, outfluxes from the films during etching and internal environment of reactor [34,35]. Generally speaking, the H-containing plasma usually leads to high polymer deposition rates, because H atoms can scavenge the F atoms to form HF molecules which cause the fluorine-poor condition, especially for Si or SiO 2 etching [36,37].…”

Section: Fc Polymer and Surface Reactionsmentioning

confidence: 99%

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

Hsiao¹,

Nguyen²,

Tsutsumi³

et al. 2021

Coatings

View full text Add to dashboard Cite

With the increasing interest in dry etching of silicon nitride, utilization of hydrogen-contained fluorocarbon plasma has become one of the most important processes in manufacturing advanced semiconductor devices. The correlation between hydrogen-contained molecules from the plasmas and hydrogen atoms inside the SiN plays a crucial role in etching behavior. In this work, the influences of plasmas (CF4/D2 and CF4/H2) and substrate temperature (Ts, from −20 to 50 °C) on etch rates (ERs) of the PECVD SiN films were investigated. The etch rate performed by CF4/D2 plasma was higher than one obtained by CF4/H2 plasma at substrate temperature of 20 °C and higher. The optical emission spectra showed that the intensities of the fluorocarbon (FC), F, and Balmer emissions were stronger in the CF4/D2 plasma in comparison with CF4/H2. From X-ray photoelectron spectra, a thinner FC layer with a lower F/C ratio was found in the surface of the sample etched by the CF4/H2 plasma. The plasma density, gas phase concentration and FC thickness were not responsible for the higher etch rate in the CF4/D2 plasma. The abstraction of H inside the SiN films by deuterium and, in turn, hydrogen dissociation from Si or N molecules, supported by the results of in situ monitoring of surface structure using attenuated total reflectance-Fourier transform infrared spectroscopy, resulted in the enhanced ER in the CF4/D2 plasma case. The findings imply that the hydrogen dissociation plays an important role in the etching of PECVD-prepared SiN films when the hydrogen concentration of SiN is higher. For the films etched with the CF4/H2 at −20 °C, the increase in ER was attributed to a thinner FC layer and surface reactions. On the contrary, in the CF4/D2 case the dependence of ER on substrate temperature was the consequence of the factors which include the FC layer thickness (diffusion length) and the atomic mobility of the etchants (thermal activation reaction).

show abstract

Section: Fc Polymer and Surface Reactionsmentioning

confidence: 99%

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

Hsiao¹,

Nguyen²,

Tsutsumi³

et al. 2021

Coatings

View full text Add to dashboard Cite

show abstract

“…It is already common knowledge, by thermodynamic laws and Arrhenius equation, that the material's temperature influences its reactivity with the environment, either in kinetic form (reaction rate), in the form of activation energy (heat required to allow the beginning of a reaction) 1 , surface temperature for processes like etch rate 2 , deposition rate 3-5 , or polymerization 4,6 of the materials exposed to plasmas. However, there are cases in which is necessary to avoid the occurrence of specific reactions by controlling the reached temperature on materials surface, such as in food sterilization processing that degrades the flavor in higher temperatures 7 , controlled solidification 8 , precipitation of unwanted second phases in metal alloys, grain growing, and phase change in ceramics 9 .…”

Section: Introductionmentioning

confidence: 99%

Determination of Surface Temperature in ICP RF Plasma Treatments of Organic Materials

et al. 2017

View full text Add to dashboard Cite

The reactions that can occur on organic materials treated in plasma enviorement are strongly affected by surface temperature, thus the sharp determination of this variable is extremely important to process control. In situ temperature measurements are often employed; however, the measured point is generally under the treated surface. If in metallic materials the high thermal conductivity minimizes this problem, in non-metallic materials processing it becomes important, because its thermal resistivity besides a high sensibility to small temperature variations. The present work uses a simulation tool to extract thermal data on Ar+O 2 RF plasma processing of Stearic Acid. Experimental data were obtained by thermocouples placed inside the samples. The extrapolation of surface temperature was performed by numerical simulation with Autodesk CFD software v.15.1. Results show that the temperature of the surface reaches values higher than the ones measured inside the sample holder. This difference of temperature is in good agreement with the visual observation of the phase transformations in the treated material, showing a simple and valuable tool to better control of plasma treatments.

show abstract

Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF₄/H₂ plasma at different substrate temperatures

Hsiao

Britun

Nguyen

et al. 2021

Plasma Processes & Polymers

View full text Add to dashboard Cite

The dependences of etching characteristics on substrate temperature (Ts, from –20 to 50°C) of the plasma‐enhanced chemical vapor deposition (PECVD) SiN films (PE‐SiN) and low‐pressure chemical vapor deposition (LPCVD) SiN films (LP‐SiN) with CF4/H2 plasma were investigated. The Fourier‐transform infrared spectroscopy shows that both film types were N–H bond‐rich films, but in different hydrogen contents (PE‐SiN 22.7 at% and LP‐SiN 3.8 at%) from the Rutherford backscattering spectroscopy analyses. A higher hydrogen content led to a thinner fluorocarbon thickness because of the reaction between hydrogen outflux and C and N to form an HCN byproduct. The etch rates (ER) for the PE‐SiN were higher than that of the LP‐SiN at all Ts, due to the different FC thickness and etching mechanisms proposed. The formation of the N−Hx layer on PE‐SiN at low temperature caused the decrease in ER. For the LP‐SiN, the weak dependences of Ts on surface structure and ER were observed.

show abstract

Role of surface temperature in fluorocarbon plasma-surface interactions

Cited by 5 publications

References 21 publications

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

Determination of Surface Temperature in ICP RF Plasma Treatments of Organic Materials

Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF₄/H₂ plasma at different substrate temperatures

Contact Info

Product

Resources

About

Role of surface temperature in fluorocarbon plasma-surface interactions

Cited by 5 publications

References 21 publications

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

On the Etching Mechanism of Highly Hydrogenated SiN Films by CF4/D2 Plasma: Comparison with CF4/H2

Determination of Surface Temperature in ICP RF Plasma Treatments of Organic Materials

Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF4/H2 plasma at different substrate temperatures

Contact Info

Product

Resources

About

Effects of hydrogen content in films on the etching of LPCVD and PECVD SiN films using CF₄/H₂ plasma at different substrate temperatures