masked ion beam lithography

MASKED ION BEAM LITHOGRAPHY

ARUNBALAJI.S

MIBL - INTRODUCTION

• Successing technology of Ion Beam Lithography• New approach for Biomaterial Patterning• It allows selected Ion beam to be allowed to fall

on the mask• Ions of Ca,Mg,Na,P are used as Sources• Technique of implanting the dopants in the

manufacturing process of semiconductors.

MIBL- Setup

Techniques in Ion Beam Lithography

• Hydrogen and helium ion beams a extracted from the suitable ion source.

• M X B mass separation unit is included.• Proper electrostatic setup is arranged to get the

parallel ion beam• The Mask is made up of Silicon, copper.• Ion Beam Induced heating on the mask is avoided

by arrangement of cooling setup for mask

MAJOR TYPES OF ION SOURCES

Liquid metal ion sources Gas field ion sources Volume Plasma sources

Liquid metal ion source

GAS FIELD ION SOURCE

Volume plasma Source• Mostly used in ion implanters, ion milling

machines and other ion accelerators• Sources of desired ions are introduced as gas.• Electron bombardment is used to ionize it.

Importance of ion beam over other

techniques• Nanofabrication without multistep process.• When a focused beam of ions is traced over a

surface, it removes material to form a trench approximately equal to the beam diameter.

• rewire integrated circuits by cutting or depositing metal film conductors.

• useful in the pre-production development phase to alter a circuit that may not be working because of a design or fabrication error

Advantages of using ions over electrons

Ions are larger than electrons, so less change in chemical nature of substrate,no x- ray emissions in the sample.

Ions are heavier than electrons . So ions gain high momentum.

Ion beam milling depends on the how much ions needed to remove the material, it is independent of the material’s chemical nature and material strength.

Material deposition on the specific sites of the circuit.

MIBL - ADVANTAGES• This method overcomes the problems of beam

dispersion and diffraction in the Optical and X-ray lithographic systems

• It reduces the multiple steps like film casting, exposure, developing and etching process as in photolithography.

• The surface chemistry of substrate is tailored better compared to photolithography.

• PMMA surface modification by calcium and phosphorous ions are used to create microwells for biomems devices

•

MIBL -APPLICATIONS• High Volume gate level printing of Field emitter

Displays(FED).• Fabrication of surface acousting wave and

microoptic devices.• Deep trenching reactive ion beam etching in

MEMS and in particular for silicon Microsystems

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