X-ray photoelectron spectroscopy analyses of metal stacks etched in Cl2/BCl3 high density plasmas

Czupryński, Piotr; Joubert, O.; Vallier, L.; Puttock, Mark; Heitzmann, M.

doi:10.1116/1.589770

Cited by 15 publications

(14 citation statements)

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“…Modern RIE equipment employs high density plasma sources and work at lower pressures, where Cl 2 /BCl 3 is the common chemistry. [1][2][3] In this case, the sidewall passivation is provided by photoresist erosion, in which carbon from the photoresist mask combines with etching gases and etch by-products to form a polymer on the sidewall of the metal stack and on the resist surface. The composition of this polymer is reported to be mainly carbon and chlorine.…”

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confidence: 99%

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Baklanov

Boullart

et al. 1999

J. Electrochem. Soc.

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The evolution of surface chemical species on etched Al (Cu) lines and films has been investigated by X‐ray photoelectron spectroscopy in a postetch cleaning process, with the aim of understanding the role of each step on the removal of the etching residues.The results from the in situ strip in downstream H2O plasma show that most of the organic species are removed by oxidation reactions, together with the majority of the Cl species. However, the sidewall polymer leaves a Cl‐containing residual film due to its high metallic content and oxidation reactions. Adding a small amount of CF4 to the H2O plasma can have some advantages mainly making the residues more water soluble. Further ex situ wet chemical treatment is needed to remove the oxide/fluoride layer formed in the in situ step. It is argued that a clean surface, consisting of Al bonded strongly to its native oxide, is essential to the reliability of the interconnect. It is also found that after dry etching there are two kinds of Cu species present at the Al surface layers. One is a CuClx residue, which can be removed effectively by the cleaning. The other is elemental Cu enrichment. Rutherford backscattering spectrometry results reveal that this enrichment distributes over a depth of about 40 nm in Al, with a peak concentration of two to three times the bulk value. © 1999 The Electrochemical Society. All rights reserved.

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confidence: 99%

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Baklanov

Boullart

et al. 1999

J. Electrochem. Soc.

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“…Photoresist mask is also crucial in these processes since the sputtered photoresist fragments are also attributed to the sidewall protection layer. 7,8 For simplicity, all the ions were grouped into one ion species ͑ion flux͒, all the neutral etchants into one neutral chemical species ͑chemical flux͒, and all the inhibitors into one inhibitor species ͑deposition flux͒. The variation of these fluxes from narrow to wide spaces is considered to be the cause for the ARDE.…”

Section: Modelingmentioning

confidence: 99%

“…4,6,7,20,21 Etchant species ͑Cl atoms and Cl 2 mol-ecules͒ have to diffuse through this inhibitor layer to react with the aluminum surface. 7,20,21 This diffusion can be slower and more difficult for Cl 2 molecules, since they are bigger and heavier. Even if, after considering diffusion through the surface layer, Cl 2 molecules are equally or more reactive than Cl atoms, there is still the recombination between the adsorbed etchant and inhibitor species to consider.…”

Section: Modelingmentioning

confidence: 99%

Modeling and simulation of feature-size-dependent etching of metal stacks

Abdollahi-Alibeik

Zheng

McVittie

et al. 2001

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

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Articles you may be interested inAtomic-scale cellular model and profile simulation of poly-Si gate etching in high-density chlorine-based plasmas: Effects of passivation layer formation on evolution of feature profiles Modeling of fluorine-based high-density plasma etching of anisotropic silicon trenches with oxygen sidewall passivation J. Appl. Phys. 94, 6311 (2003); 10.1063/1.1621713Modeling oxide etching in a magnetically enhanced reactive ion plasma using neural networks Aspect ratio dependent plasma-induced charging damage in rf precleaning of a metal contact Aspect ratio dependent etching ͑ARDE͒ has often been observed in various etching processes. During etching of metal films in a high density plasma reactor, this phenomenon is more prominent. With a high amount of ARDE present, the narrow spaces will not be cleared unless there is enough overetch, which removes an excessive amount of the underlying layers. The main focus of this article is on the understanding of the mechanisms behind metal ARDE. The results from an extensive design of experiments on the subject were utilized for this study. SPEEDIE, the Stanford etching and deposition profile simulator, was used to develop and test appropriate models. The Langmuir adsorption model with added surface recombination of the adsorbed species, both etchants and inhibitors, was used to model the phenomenon. The added surface recombination acts as the major species loss mechanism on the feature sidewalls. The simulation results indicate that a process with inhibitors, which are highly adhesive to the metal surface and which do not like to recombine with the etchants to form volatile products, will lead to a low degree of ARDE. This is in agreement with experimental results which showed that the addition of CHF 3 to the Al etch process helps to reduce the ARDE in narrow space regions.

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“…1) In the RIE of aluminum (Al) using BCl 3 /Cl 2 gas, it is well known that C atoms generated from the resist react with Cl 2 in the etching gas to produce polymer, deposits on the pattern sidewall, suppressing sideetching and giving an anisotropically etched profile. 2) Tanaka et al clarified that B atoms obtained through dissociation of BCl 3 gas by plasma are present in this passivation layer on the sidewall. 3) Furthermore, various additive gases to main etching gas have been studied to realize the effective formation of a passivation layer on the sidewall.…”

Section: Introductionmentioning

confidence: 99%

Effect of CHF₃ Addition on Reactive Ion Etching of Aluminum Using Inductively Coupled Plasma

Saito

Sugita

Tonotani

2005

Jpn. J. Appl. Phys.

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The role of CHF3 gas addition in reactive ion etching (RIE) processes using inductively coupled plasma for aluminum wirings were investigated. With increasing of the amount of CHF3 gas addition to the etching gas, the pattern profile changed from reverse to ordinary taper and the pattern width increased. It was considered that by adding CHF3 to the main etching gas, a larger amount of passivation layer deposited on the sidewall of the resist and Al pattern, which suppressed side etching of the pattern. To clarify the role of CHF3 addition, XPS, FT-IR and TDS analyses were carried out to study the structure of the passivation layer. Consequently, it is considered that the pattern sidewall is composed of AlF3, an organic polymerized film and a passivation layer including ammonium salt and B oxide. Due to the addition of CHF3 gas into the etching gas, AlF3 is additionally formed, which is deposited on the pattern sidewall, resulting in the change of the etched pattern profile and width.

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X-ray photoelectron spectroscopy analyses of metal stacks etched in Cl2/BCl3 high density plasmas

Cited by 15 publications

References 14 publications

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Modeling and simulation of feature-size-dependent etching of metal stacks

Effect of CHF₃ Addition on Reactive Ion Etching of Aluminum Using Inductively Coupled Plasma

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X-ray photoelectron spectroscopy analyses of metal stacks etched in Cl2/BCl3 high density plasmas

Cited by 15 publications

References 14 publications

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Analyses of Post Metal Etch Cleaning in Downstream H 2 O ‐ Based Plasma Followed by a Wet Chemistry

Modeling and simulation of feature-size-dependent etching of metal stacks

Effect of CHF3 Addition on Reactive Ion Etching of Aluminum Using Inductively Coupled Plasma

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Effect of CHF₃ Addition on Reactive Ion Etching of Aluminum Using Inductively Coupled Plasma