Fundamental physical chemistry of ultraprecision silicon etching tonanometre dimensions

Información del proyecto

Identificador del acuerdo de subvención: BRPR970588

Proyecto cerrado

Fecha de inicio 1 Febrero 1998

Fecha de finalización 30 Abril 2001

Financiado con arreglo a

• Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Coste total

Sin datos

Aportación de la UE

Sin datos

Coordinado por

THE UNIVERSITY OF LIVERPOOL
United Kingdom

Objetivo

Objectives and content
The aim of the project is to achieve a fundamental
physicochemical understanding of the kinetics an
mechanism of chemical and electrochemical dissolution of
silicon in aqueous KOH with a view to develop the next
generation of ultra-high precision anisotropic wet
chemical etching techniques with enhanced reliability in
both anisotropic ratios and surface finish for large area
devices. It is widely accepted that the crystal
orientation sensitivity resulting in the anisotropic
dissolution of Si is determined by orientation dependent
surface chemistry. The present project is based on a
fundamental Physical Chemistry approach, bringing
together advanced electrochemical and surface science
techniques for the understanding of the mechanism of
anisotropic etching of silicon and of the origin of
pyramids often observed in the etching of micromachined
structures. The main industrial objectives are
reliability in surface finish, with a surface roughness
better than 4 nm rms, and the production of etched
surfaces with anistropic ratios between the { 100} and {
111 } surfaces better than 140:1 and a ratio
reproducibility better than 5%.
The proposed research programme capitalises on recent
advances in instrumentation and in the study of the
physical chemistry of semiconductor electrodes. The
proposers intend to establish a link between results
obtained under UHV conditions with experiments in the
condensed phase. Surface science techniques give a
unique possibility for the characterisation of the state
of a surface and allows to monitor the way in which
organic absorbates interact with single crystal silicon
by LEED, Programmed Thermal Desorption and High
Resolution Electron Energy Loss Spectroscopy. In
addition, other structure and chemical sensitive
techniques, such as XPS provide a wealth of surface
information that has not been employed until now for the
characterisation of the Si-aqueous KOH interface in the
presence of organic additives.
Simultaneously with this type of measurements, the
proposers will investigate the Si-aqueous KOH interface
by a variety of powerful electrochemical techniques, such
as in-situ AFM, luminescence emission, FTIR modulated
Reflectance Spectroscopy, AC impedance spectroscopy and
phocurrent, in an attempt to understand the band
structure at the interface and the mechanism of
dissolution of Si. It is of particular importance to
understand if the anisotropic dissolution reaction
follows a chemical or an electrochemical mechanism, or
both simultaneously, and it is expected that the
combination of electrochemistry and surface science
methods will provide the necessary fundamental
understanding for the development of practical etching
baths with far superior performances than those that
achieved at present by a trial and error approach.
The main scientific objectives of the proposal are:
To study of the elementary steps in the dissolution
reaction of Si
To determine the origin of anisotropy and of the
chemical factors affecting anisotropic ratios.
The investigate the physical chemistry of organic
additives in relation to the surface chemistry of silicon
To establish a relationship between semiconducting
properties and Si etching.
The industrial application of the proposed research are
to develop:
New etching formulations leading to a surface roughness
of less than 4 nm rms
Methods for the in situ measurement and control of
anisotropic ratios of etching baths
New methodologies for etching bath design.

Ámbito científico (EuroSciVoc)

• ciencias naturales › ciencias químicas › electroquímica
• ciencias naturales › ciencias físicas › electromagnetismo y electrónica › dispositivo semiconductor
• ciencias naturales › ciencias químicas › química inorgánica › metaloides
• ciencias naturales › ciencias químicas › química física
• ciencias naturales › ciencias físicas › óptica › espectroscopia

Palabras clave

• Nanotechnology

Programa(s)

• FP4-BRITE/EURAM 3 - Specific research and technological development programme in the field of industrial and materials technologies, 1994-1998

Tema(s)

• 0202 - New methodologies for product design and manufacture

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

CSC - Cost-sharing contracts

Coordinador

THE UNIVERSITY OF LIVERPOOL

• Aportación de la UE: Sin datos
• Dirección: Crown Street ; L69 7ZD LIVERPOOL ; Reino Unido
• Coste total: Sin datos

Participantes (5)

Druck Limited

Reino Unido

• Aportación de la UE: Sin datos
• Dirección: Fir Tree Lane ; LE6 0FH Groby
• Coste total: Sin datos

Rijksuniversiteit Utrecht

Países Bajos

• Aportación de la UE: Sin datos
• Dirección: 1,Princetonplein 1 ; 3584 CC Utrecht
• Coste total: Sin datos

Siemens AG

Alemania

• Aportación de la UE: Sin datos
• Dirección: 13623 Berlin
• Coste total: Sin datos

UNIVERSITY OF ST ANDREWS

Reino Unido

• Aportación de la UE: Sin datos
• Dirección: Purdie Building ; KY16 9ST ST ANDREWS
• Coste total: Sin datos

University of Limerick

Irlanda

• Aportación de la UE: Sin datos
• Dirección: The National Technological Park ; 61 Limerick
• Coste total: Sin datos