Step coverage prediction in low-pressure Chemical Vapor Deposition

Gregory Raupp, T. S. Cale

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

A mathematical model incorporating simultaneous one-dimensional Knudsen diffusion and chemical reaction is employed to analyze transient behavior during low-pressure chemical vapor deposition (CVD) in features of arbitrary geometry on patterned semiconductor wafers. For a given feature geometry and CVD reaction, the dimensionless model equations reveal that step coverage is controlled by the value of a single dimensionless parameter that represents the ratio of a characteristic deposition rate to a characteristic reactant diffusion rate. Temperature, reactant partial pressure at the feature mouth, and aspect ratio are the process parameters that may be varied to improve step coverage for a given CVD chemistry. The proper directions of change for temperature and reactant pressure are determined by the parameters of the intrinsic reaction rate expression for the particular CVD chemistry of interest. Deposition of amorphous SiO2 from TEOS (tetraethyl silicate) is considered as a specific example. The model predicts that step coverage improves with decreasing temperature and increasing pressure of TEOS at the feature mouth, in agreement with experimental results. Calculation of reactive sticking coefficients shows that this diffusion-reaction model is consistent with the modification of the line-of-sight model that invokes low sticking coefficients to explain conformal step coverage.

Original languageEnglish (US)
Pages (from-to)207-214
Number of pages8
JournalChemistry of Materials
Volume1
Issue number2
StatePublished - 1989

Fingerprint

Low pressure chemical vapor deposition
Chemical vapor deposition
Silicates
Geometry
Deposition rates
Partial pressure
Temperature
Reaction rates
Aspect ratio
Chemical reactions
Mathematical models
Semiconductor materials

ASJC Scopus subject areas

  • Materials Chemistry
  • Materials Science(all)

Cite this

Step coverage prediction in low-pressure Chemical Vapor Deposition. / Raupp, Gregory; Cale, T. S.

In: Chemistry of Materials, Vol. 1, No. 2, 1989, p. 207-214.

Research output: Contribution to journalArticle

@article{4a96e8b0526a431e9ee4e71fd47f11bb,
title = "Step coverage prediction in low-pressure Chemical Vapor Deposition",
abstract = "A mathematical model incorporating simultaneous one-dimensional Knudsen diffusion and chemical reaction is employed to analyze transient behavior during low-pressure chemical vapor deposition (CVD) in features of arbitrary geometry on patterned semiconductor wafers. For a given feature geometry and CVD reaction, the dimensionless model equations reveal that step coverage is controlled by the value of a single dimensionless parameter that represents the ratio of a characteristic deposition rate to a characteristic reactant diffusion rate. Temperature, reactant partial pressure at the feature mouth, and aspect ratio are the process parameters that may be varied to improve step coverage for a given CVD chemistry. The proper directions of change for temperature and reactant pressure are determined by the parameters of the intrinsic reaction rate expression for the particular CVD chemistry of interest. Deposition of amorphous SiO2 from TEOS (tetraethyl silicate) is considered as a specific example. The model predicts that step coverage improves with decreasing temperature and increasing pressure of TEOS at the feature mouth, in agreement with experimental results. Calculation of reactive sticking coefficients shows that this diffusion-reaction model is consistent with the modification of the line-of-sight model that invokes low sticking coefficients to explain conformal step coverage.",
author = "Gregory Raupp and Cale, {T. S.}",
year = "1989",
language = "English (US)",
volume = "1",
pages = "207--214",
journal = "Chemistry of Materials",
issn = "0897-4756",
publisher = "American Chemical Society",
number = "2",

}

TY - JOUR

T1 - Step coverage prediction in low-pressure Chemical Vapor Deposition

AU - Raupp, Gregory

AU - Cale, T. S.

PY - 1989

Y1 - 1989

N2 - A mathematical model incorporating simultaneous one-dimensional Knudsen diffusion and chemical reaction is employed to analyze transient behavior during low-pressure chemical vapor deposition (CVD) in features of arbitrary geometry on patterned semiconductor wafers. For a given feature geometry and CVD reaction, the dimensionless model equations reveal that step coverage is controlled by the value of a single dimensionless parameter that represents the ratio of a characteristic deposition rate to a characteristic reactant diffusion rate. Temperature, reactant partial pressure at the feature mouth, and aspect ratio are the process parameters that may be varied to improve step coverage for a given CVD chemistry. The proper directions of change for temperature and reactant pressure are determined by the parameters of the intrinsic reaction rate expression for the particular CVD chemistry of interest. Deposition of amorphous SiO2 from TEOS (tetraethyl silicate) is considered as a specific example. The model predicts that step coverage improves with decreasing temperature and increasing pressure of TEOS at the feature mouth, in agreement with experimental results. Calculation of reactive sticking coefficients shows that this diffusion-reaction model is consistent with the modification of the line-of-sight model that invokes low sticking coefficients to explain conformal step coverage.

AB - A mathematical model incorporating simultaneous one-dimensional Knudsen diffusion and chemical reaction is employed to analyze transient behavior during low-pressure chemical vapor deposition (CVD) in features of arbitrary geometry on patterned semiconductor wafers. For a given feature geometry and CVD reaction, the dimensionless model equations reveal that step coverage is controlled by the value of a single dimensionless parameter that represents the ratio of a characteristic deposition rate to a characteristic reactant diffusion rate. Temperature, reactant partial pressure at the feature mouth, and aspect ratio are the process parameters that may be varied to improve step coverage for a given CVD chemistry. The proper directions of change for temperature and reactant pressure are determined by the parameters of the intrinsic reaction rate expression for the particular CVD chemistry of interest. Deposition of amorphous SiO2 from TEOS (tetraethyl silicate) is considered as a specific example. The model predicts that step coverage improves with decreasing temperature and increasing pressure of TEOS at the feature mouth, in agreement with experimental results. Calculation of reactive sticking coefficients shows that this diffusion-reaction model is consistent with the modification of the line-of-sight model that invokes low sticking coefficients to explain conformal step coverage.

UR - http://www.scopus.com/inward/record.url?scp=0005248892&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0005248892&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0005248892

VL - 1

SP - 207

EP - 214

JO - Chemistry of Materials

JF - Chemistry of Materials

SN - 0897-4756

IS - 2

ER -