(Invited) Plasma Etching Technology Challenges for Future CMOS Fabrication Based on Microwave ECR Plasma

Izawa, Masaru; Tagaya, Motohiro; Yasui, Naoki; Morimoto, Michikazu

doi:10.1149/06604.0143ecst

Cited by 12 publications

(8 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The TM frequency for both source and wafer bias was fixed at 1 kHz, and the DC was varied for evaluation. The typical plasma potential is <15 V. 45) The contribution of ions to etching is negligible during the off period. The wafer stage has an electrode cover made of an insulator, which insulates the wafer RF bias.…”

Section: Experimental Methodsmentioning

confidence: 99%

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Morimoto

Matsui

Ikeda

et al. 2023

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

Highly selective Si3N4 etching on Si was achieved in a CH3F/O2/Ar plasma using pulsed-microwave plasma and time-modulation (TM) bias. The Si3N4/Si selectivity reached infinity at a peak-to-peak voltage (Vpp) of 240 V. The effect of pulsed-microwave on CH3F gas dissociation for highly selective Si3N4 etching was investigated by deposited film analysis, optical emission spectroscopy (OES), and ion current flux measurements. As the duty cycle of the pulsed-microwave was decreased, the plasma density during the pulse on period decreased and the CH/H ratio increased. The pulsed-microwave plasma produced low-dissociation radicals by providing a low plasma density. The low-dissociation radicals in the CH3F plasma formed a fluorine (F)-rich hydrofluorocarbon (HFC) layer on the Si3N4 wafer surface. The F-rich HFC layer promotes Si3N4 etching even at low ion energy, where Si etching does not proceed, and enables highly selective Si3N4 etching on Si.

show abstract

Section: Experimental Methodsmentioning

confidence: 99%

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Morimoto

Matsui

Ikeda

et al. 2023

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…By coupling resonant (2.45 GHz) microwave power via a waveguide into reactive process gases, a glow discharge was generated by an electron-cyclotron-resonance reaction. This mechanism enabled high-radical density at low pressure and was combined with unique time-modulation functions of both the microwave power and RF-wafer bias to precisely control the reactant species within the gratings 13 .…”

Section: Experimental Procedures 21 Pattern Evaluationmentioning

confidence: 99%

Evaluation of TiN hardmask films to prevent line wiggling due to plasma-induced film stress

Turnquist

Kofuji

Strzalka

et al. 2023

Advanced Etch Technology and Process Integration for Nanopatterning XII

View full text Add to dashboard Cite

The impact of both intrinsic and plasma-induced stress of a TiN hardmask on line wiggling was investigated via etching of p-SiOCH with 28 nm pitch, line and space (L/S) EUV resist patterning. Experimental stacks included crystalline PVD TiN with an intrinsic stress of +0.1 GPa and several PEALD TiN films with varying crystallinity and intrinsic stresses ranging from -3.6 GPa (compressive) to +0.2 GPa (tensile). Results confirmed that reduction of intrinsic TiN stress can prevent wiggling1 when the mask is not exposed to plasma during process flow. However, when TiN is exposed to plasma as in a typical back end of line (BEOL) process2-3, compressive stress increased in all films and resulted in wiggling even in the patterned PVD TiN sample with low intrinsic stress. This global increase in compressive stress due to plasma exposure did not correlate with intrinsic stress values, therefore, this work suggests a greater focus should be placed on plasma-induced stress to avoid line wiggling when selecting a TiN film. Further investigation found that increased surface roughness of the TiN mask can decrease the risk of wiggling, and that surface roughness is influenced by p-SiOCH etch selectivity, indicating mask surface roughness should also be considered when evaluating line wiggling in BEOL, p-SiOCH etching.

show abstract

“…This includes electron cyclotron resonance (ECR) based low-pressure plasmas that are utilized for etching conducting and semiconducting materials. 23 A typical ECR reactor is shown in Fig. 5.…”

Section: Microwave Plasmasmentioning

confidence: 99%

“…Several variants of microwave plasmas [operating in the ultra high frequency (UHF) or super high frequency (SHF) bands] are used for plasma processing. This includes electron cyclotron resonance (ECR) based low-pressure plasmas that are utilized for etching conducting and semiconducting materials 23 . A typical ECR reactor is shown in Fig.…”

Section: Plasma Sources In the Semiconductor Industrymentioning

confidence: 99%

Modeling of plasma processing reactors: review and perspective

Rauf,

Bera,

Kenney

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

View full text Add to dashboard Cite

.Low temperature plasmas (LTPs) are widely used in the semiconductor industry to etch, deposit, modify, and pattern thin films during the fabrication of integrated circuits. Modeling techniques used to simulate industrial processing plasmas are reviewed in this article. The authors also provide their perspective on areas of highest research and development need. The most common plasma sources used in the semiconductor industry are capacitively coupled plasmas, inductively coupled plasmas, magnetrons, magnetized and unmagnetized microwave plasmas, and remote plasmas. These LTP systems can be simulated using global, fluid, and particle-based kinetic modeling techniques. A variety of hybrid methods have also been developed that supplement fluid plasma models with kinetic models for aspects of the plasma behavior. The industry expects plasma models to be quantitatively accurate, so they can be used as an LTP system design tool. The optimal models are usually a thoughtful blend of precise physics and experimentally guided refinements. The authors highlight the benefit and need of multi-faceted plasma model validation studies in which plasma sources are first characterized using a variety of complementary diagnostics. Quantitatively accurate models for these plasmas are then developed to test the accuracy of key aspects of the plasma including the electron energy distribution function, ion energy distribution function at surfaces, charged and neutral species densities or fluxes, and gas temperature. An important aspect of the validation exercise is the development of the plasma chemistry mechanisms and models for plasma–surface interaction.

show abstract

(Invited) Plasma Etching Technology Challenges for Future CMOS Fabrication Based on Microwave ECR Plasma

Cited by 12 publications

References 10 publications

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Evaluation of TiN hardmask films to prevent line wiggling due to plasma-induced film stress

Modeling of plasma processing reactors: review and perspective

Contact Info

Product

Resources

About

(Invited) Plasma Etching Technology Challenges for Future CMOS Fabrication Based on Microwave ECR Plasma

Cited by 12 publications

References 10 publications

Highly selective Si3N4 etching on Si using pulsed-microwave CH3F/O2/Ar plasma

Highly selective Si3N4 etching on Si using pulsed-microwave CH3F/O2/Ar plasma

Evaluation of TiN hardmask films to prevent line wiggling due to plasma-induced film stress

Modeling of plasma processing reactors: review and perspective

Contact Info

Product

Resources

About

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma

Highly selective Si₃N₄ etching on Si using pulsed-microwave CH₃F/O₂/Ar plasma