Polysilicon gate etching in high density plasmas. V. Comparison between quantitative chemical analysis of photoresist and oxide masked polysilicon gates etched in HBr/Cl{sub 2}/O{sub 2} plasmas

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena

DOI:https://doi.org/10.1116/1.589259· OSTI ID:450295

Bell, F H; Joubert, O ^[1]

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1. France Telecom, CNET BP 98, 38243 Meylan Cedex (France)

We have used x-ray photoelectron spectroscopy (XPS) to study the chemical constituents present on the surfaces after etching of poly-Si features masked with photoresist or oxide patterns. The wafers were etched in a low pressure, high density plasma, helicon source using a HBr/Cl{sub 2}/O{sub 2} gas mixture. The O{sub 2} gas flow rate was tuned to obtain anisotropic etching profiles by forming an SiO{sub 2} like layer on the sidewalls of the features and maximizing the polysilicon/gate oxide selectivity. Electrostatic charging of insulating surfaces and geometric shadowing of photoelectrons by adjacent photoresist lines were performed to differentiate the photoemission signals from the tops, sidewalls, and bottoms of the features. XPS analyses have shown that the passivation layer formed on the polysilicon sidewalls during etching is a chlorine rich silicon oxide film with both type of masks. This film contains a low carbon concentration when resist is used as a mask. The similar thickness and constitution of the sidewall for oxide and photoresist masked poly-Si samples indicate that the nature of the mask material has no significant effect on the sidewall passivation mechanism. {copyright} {ital 1997 American Vacuum Society.}

• OSTI ID: 450295
• Journal Information: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena, Journal Name: Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena Journal Issue: 1 Vol. 15; ISSN JVTBD9; ISSN 0734-211X
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
BROMINE
CHLORINE
ELECTROSTATICS
ETCHING
PHOTOELECTRON SPECTROSCOPY
PLASMA
POLYMERS
QUANTITATIVE CHEMICAL ANALYSIS
SILICON
SPUTTERING
X RADIATION