This document provides an overview of metallization for integrated circuits. It discusses the requirements and purposes of metallization, including interconnecting thousands of devices on chips. Two common metallization methods described are vacuum evaporation and sputter deposition. Vacuum evaporation locally heats a material source to vaporize and deposit the metal film, while sputter deposition uses ion momentum from a plasma to eject atoms from a target onto the substrate. The document outlines the apparatus and processes for each technique.

1. DEPARTMENT OF ELECTRONICS & COMMUNICATION
ENGINEERING
PONDICHERRY UNIVERSITY
TOPIC
PRESENTATION ON METALLIZATION
PRESENTED BY
GANESHKUMAR.P

2. OUTLINES
 Metallization
 Requirement of Metallization
 Schematic Representation
 MetallizationApplication inVLSI
 Methods of Metallization
 Problems in Metallization
 Vacuum Evaporation
 Different Part of the Apparatus
 Diagram of Local EvaporationTechnique
 Sputter Deposition
 Apparatus
 Advantages
 Disadvantages

3. METALLIZATION
 Metallization is the process by which the components of the ICS are
interconnected by aluminum conductor or metallization is the process that
connects individual devices together by means of microscopic wires to form
circuits.
 This process produces a thin film of metal layer that will serve as the required
conductor pattern for the interconnection of the various components on the
chips.
 With the help of metallization thousand of devices can be interconnected using
fine line metal patterns.
 The metal films can be formed by various methods like ChemicalVapor
Deposition (CVD) and PhysicalVapor Deposition(PVD).

4. REQUIREMENTS OF METALLIZATION
 Low resistivity.
 Easy to form.
 Easy to etch for pattern generation.
 Should be Oxidizable.
 Mechanically stable.
 Smooth surface.
 Should be stable towards high temperature dry or wet oxidation etc.
 Should not contaminate wafers.
 Good life time.
 Low contact resistance to devices.
 Reliable long term operation.
 e

5. SCHEMATIC REPRESENTATION
ADVENTAGE:
• GoodAdherence.
• Easy ti Deposit.
• Good Mechanical Bonds.
• Good Resistance.
DISADVENTAGE:
• Aluminum reacts with gold to form a
metallic compound called purple plague.
• During packing operation, if temperature
goes beyond 500 degree, Aluminum can
get fused and can penetrate the oxide to
cause short circuit.

6. METALLIZATION APPLICATION VLSI &
METHODS OF METALLIZATION
APPLICATION:
 Used to Gates for MOSFET.
 Used to make Ohmic Contacts.
 Interconnects.
 Used to connect thousand of MOSFET
internally.
 Provides connection to the outside world.
METHODES:
 Sputtering (SPUT).
 Evaporation(EVA).
 Physical vapour Deposition (PVD).
 ChemicalVapour Deposition (CVD).

7. PROBLEMS IN METALLIZATION
1. DEPOSITION:
Impurities in the films, adhesion and thickness non uniformity are two various problems,
related to deposition. Impurities in the films can be minimized by using pure evaporation
and sputtering sources, high vacuum and clean surface. Cracks in the deposition are
because of poor adhesion or surface unevenness. Controlling these effects will eliminate
cracks.
2. PROCESSING:
Different stages of IC processing utilize metallization. Gate metal is deposited in early
stages and the contact metal towards the end. Thus the gate metal in subjected to
considerable processing while the contact metal experiences very little processing steps.

8. PROBLEMS IN METALLIZATION
3. METALLURGICAL AND CHEMICAL INTERACTION:
Metallization can be completely destroyed by reaction induced by thermally activated
process with the substrates or layer the top.
4. ELECTRO MIGRATION:
The corresponding current density becomes large. High current densities can cause devices
failure due to Electromigration.

9. VACUUM EVAPORATION:
In this process the material to be evaporated is heated in a evacuated chamber so that it attains a
gaseous state. Vapour of thin material transvers the space from the source to the substrate on which
they eventually land. The pressure is maintained well below 10 torr.

10. DIFFERENT PARTS OF THE
APPARATUS
 ROUGHING PUMP: It is used to evacuate the chamber.
 HIGHVACUUM PUMP: Maintain high vacuum by reducing pressure with the help by
nitrogen cooled trap.
 SPUTTER GAS: Is used to clean the surface of the wafer.
The evaporation technique is of following two type:
 GLOBAL: Energy is supplied to the entire mass of the source present. The major
problem with this scheme is that the boat containing the source material also gets
evaporated and thus contaminates the deposition film.
 LOCAL: It employs laser beam and electron beam evaporation. In this systems a beam
of focused electron is allowed to be incident on the sources contained in the crucible. The
beam causes the source material to metal and vaporize locally at the point of incidence of
the beam.

11. DIAGRAM OF LOCAL EVAPORATION
TECHNIQUE

12. SPUTTER DEPOSITION
PRICIPAL:
Sputtering is driven by momentum exchange between the ions and
atoms in the material due to collision. The process can be thought of as atomic
billiards, with the ion striking a large cluster of close-packed atoms.

13. APPARATUS
The required breakdown voltage is given by the Pascal’s Law
V α P*L
log P*L+b
P= Chamber Pressure
L= Electrode Spacing
b= is a Constant

14. APPARATUS

15. ADVANTAGES & DISADVANTAGES
ADVANTAGES:
 The ability to deposit a wide variety
of metal and insulation.
 The capability of cleaning the
substrate prior to film deposition.
DISADVANTAGES:
 This process damages the surface of
the substrate.

16. THANK YOU
FOR YOUR ATTENTION