Selective and anisotropic reactive ion etch of LPCVD silicon nitride with CHF3 based gases

Mele, T.C.; Nulman, J.; Krusius, J.P.

doi:10.1116/1.582863

Cited by 29 publications

(18 citation statements)

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“…A similar cyclic method as discussed in the previous section, where etch cycles were interleaved by N 2 flushing steps, was investigated using a well-known plasma process with CHF 3 and O 2 . 12 Process parameters can be found in Table I. Results from an experiment with decreasing etch cycle duration ͑but a constant total etch time of 4 min͒ are depicted in Fig.…”

Section: Cyclic Etching Of Sin Xmentioning

confidence: 99%

Fabrication of a hard mask for InP based photonic crystals: Increasing the plasma-etch selectivity of poly(methyl methacrylate) versus SiO2 and SiNx

Wüest

Strasser

Robin

et al. 2005

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

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We introduce cyclic reactive ion etching processes for SiO2 and SiNx hard masks where the fluorine-based etch steps are interleaved with N2 flushing steps in order to improve the selectivity to electron-beam resists. For SiO2 etching an etch-step duration of 30s resulted in a doubled selectivity of almost 4:1 between SiO2 and poly(methyl methacrylate) (PMMA) due to a reduced thermal load. We established the pattern transfer from a 200nm thick PMMA resist into a 600nm thick SiO2 layer for 200nm diameter holes. For SiNx etching we demonstrate improved sidewall verticality, an enhanced etch rate, and suppressed redeposition of etch byproducts for a cyclic process. With the use of an additional 30nm titanium intermediate layer we show an excellent overall selectivity between SiNx and PMMA of almost 5:1. This process is applied to the fabrication of planar photonic-crystal devices with 3.5μm deep holes in an InP based slab waveguide with an initial PMMA layer thickness of 220nm.

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Section: Cyclic Etching Of Sin Xmentioning

confidence: 99%

Fabrication of a hard mask for InP based photonic crystals: Increasing the plasma-etch selectivity of poly(methyl methacrylate) versus SiO2 and SiNx

Wüest

Strasser

Robin

et al. 2005

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

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“…First, when sidewall passivation layers are formed during etching, they can be controlled by a careful balance of the etching chemistry. 3,20,22,23,26 Notably, oxygen can be added to reduce fluorocarbon depositions when etching Si, SiO 2 , or SiN x in fluorocarbon-based gas chemistries. The second concept can, e.g., be found in various implementations of what became known as the Bosch process.…”

Section: A Comparison Of Etching Concepts For Vertical Sidewall Nanomentioning

confidence: 99%

“…11,21 Moreover, O 2 addition to a CHF 3 plasma has been observed on several instances to increase the etching rate of SiN x . 22,23 The C 1s spectra of all samples are depicted in Fig. 2.…”

Section: B Surface Analysis and Verification Of Process Mechanismmentioning

confidence: 99%

“…The literature provides a lot of useful information on this topic since plasma-assisted dry-etching of Si, SiO 2 , and SiN x has been studied for many years. [8][9][10][11][12]15,16,[20][21][22][23][26][27][28][29][30][31][32][33][34] In fluorocarbon-based gas chemistries, the formation of thin films on etched surfaces was reported at an early stage. 21,32 The thickness d of these films depends on the material, 11 d Si Ͼ d SiN x Ͼ d SiO 2 , as well as on temperature 26 and self-bias 15,33,34 in the plasma reactor.…”

Section: B Potential Application Of Process Concept To Silicon Dioxidementioning

confidence: 99%

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Silicon nitride hardmask fabrication using a cyclic CHF3-based reactive ion etching process for vertical profile nanostructures

Kaspar

Jeyaram

Jäckel

et al. 2010

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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A cyclic approach to silicon nitride dry-etching is presented, which differs in concept from most established high aspect ratio etching processes. Alternating steps of CHF3 etching and oxygen plasma treatment are applied to form vertical sidewalls. During the CHF3 etching step, an etch-inhibiting fluorocarbon film gradually forms on silicon nitride surfaces, whereas the oxygen plasma step removes the fluorocarbon layer and restores the bare nitride surface. By adjusting the timing between the two steps, the etch-inhibition by the fluorocarbon film can be controlled to yield vertical sidewalls. Using x-ray photoelectron spectroscopy, the formation and removal of the fluorocarbon film are confirmed, and its chemical composition is analyzed. The authors show the influence of cycle step duration on etched sidewall angles and present the results of an optimized set of etching parameters for smooth and vertical sidewalls. By feeding only one gas at a time to the plasma reactor, they avoid having to control the delicate balance between the fluxes of species that deposit and etch the fluorocarbon film. This makes their process very robust and removes the highly variable effects of reactor wall conditions. Finally, the authors comment on the feasibility of implementing a process for etching silicon dioxide in a similar fashion.

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“…The etching mechanism of silicon using CF 4 10 2 mixtures can be said as well established [3][4][5]. Numerous articles on the etching of silicon nitride films in reactive ion etching (RIE) environments using fluorocarbon(CF 4 ) based plasmas with oxygen additions have also been published [6][7][8]. In this work, the study of dry etching of silicon nitride layer under a CF 4 1O 2 gas mixture using reactive ion etching (RIE) process will be reported.…”

Section: Introductionmentioning

confidence: 99%

DOE study on etching rate of silicon nitride (Si<inf>3</inf>N<inf>4</inf>) layer via RIE nitride etching process

Ghazali¹,

Soetedjo²,

Ngah³

et al. 2008

2008 IEEE International Conference on Semiconductor Electronics

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In the electronic device fabrication, etching is one of the important processes to do. For this work, the dry etching was done to silicon nitride layer under a CF 4 / O 2 gas mixture using reactive ion etching (RIE) process has been investigated. This etching process was carried out at a room temperature with gas pressure of 500 mTorr, RF power of 60-80 W, O 2 and CF 4 flow rate of 5-10 seem and 40-50 seem respectively. From the process, a statistical method of Design of Experiment (DOE) Pro XL software was utilized for appropriate analysis.

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Selective and anisotropic reactive ion etch of LPCVD silicon nitride with CHF3 based gases

Cited by 29 publications

References 0 publications

Fabrication of a hard mask for InP based photonic crystals: Increasing the plasma-etch selectivity of poly(methyl methacrylate) versus SiO2 and SiNx

Fabrication of a hard mask for InP based photonic crystals: Increasing the plasma-etch selectivity of poly(methyl methacrylate) versus SiO2 and SiNx

Silicon nitride hardmask fabrication using a cyclic CHF3-based reactive ion etching process for vertical profile nanostructures

DOE study on etching rate of silicon nitride (Si<inf>3</inf>N<inf>4</inf>) layer via RIE nitride etching process

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