Aluminium thick film conductors offer very large cost advantages compared with noble metals and can also improve
the reliability of circuits by eliminating gold-aluminium interfaces and their attendant intermetallic phenomena. To
date however, it has not been possible to produce aluminium thick film conductors which are ultrasonically
bondable to aluminium-silicon wire.This paper describes a study of the microstructure and line profile of a commercially available aluminium thick
film paste as a function of firing schedule. Scanning electron microscopy has revealed the mechanisms which control
the sintering process and has suggested a revised firing schedule. It is shown that firing schedules exist which yield
conductors with adequate ultrasonic bondability and conductivity. The results of bond ageing experiments on bond
strength and conductivity are given for periods of up to 1200 h at temperatures of 60&#8211;200&#8451;.It is shown that bonds of aluminium wire to aluminium thick film are resistant to loss of bond strength but suffer
from loss of conductivity on ageing at 150&#8451;.

R. E. Cooper

P. F. T. Linford

J.  Savage

An Improved Thick Film Aluminium Conductor Process

Capacitors have been prepared from N2-doped, triode sputtered Tantalum films by conventional anodization and
photolitographic techniques.NiCr&#8211;Au, Ta&#8211;Ti&#8211;Pd&#8211;Au, Ta&#8211;NiCr&#8211;Pd&#8211;Au have been used as counterelectrode materials and the a.c. and d.c. properties of the capacitors have been compared.It has been found that a doped Ta thin layer deposited by sputtering between the dielectric and the top electrode
does not negatively affect the capacitors characteristics; moreover, a thermal treatment at temperatures as high
as 350&#8451; can be tolerated.If the Ta film deposited after the dielectric formation is used for resistive elements, a fully compatible R&#8211;C
process is obtained which requires only two vacuum deposition cycles and four photolithographic steps.

G. P. Ferraris

R.  May

Tantalum Thin Film Capacitors With Various Types of
Counterelectrodes

New conductor pastes have made possible great improvements in the loss characteristics of thick film microwave
integrated circuits. This paper presents data on the microwave characteristics of transmission structures made from
newly developed copper, silver and gold conductor pastes on alumina and garnet substrates. The resistivity and
microstructure for each conductor material was examined for correlation with microwave properties. These data
show that thick film circuits can give excellent performance through 18 GHz.

R. Wayne Johnson

Phil W. Rich

Debbie D. Rich

Larry K. Wilson

Advances in Thick Film Conductors for Microwave Integrated Circuits

Two different systems of light-sensitive resist materials precoated on carrier foils and their potential applications for
thickfilm-technology and high quality printed circuits are described. In addition to 25 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x03BC;</mml:mi></mml:math>m diazo screen printing film
already accepted in this field, new experimental films up to 70 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x03BC;</mml:mi></mml:math>m thickness can be provided. They show excellent
shelf-life and can be transferred to the screen and developed after exposure simply with water. The second system is
a 12 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>&#x03BC;</mml:mi></mml:math>m positive dry film resist based on the same chemistry as all positive liquid resists. After lamination to a
substrate it can be exposed directly on the resist. It gives better resolution than negative dry film resists and offers a
potential for multiple exposure. Thicker positive dry films are possible using a new positive system without diazo
compounds.

H.  Ruckert

New Light-Sensitive Positive-Working Thick Resist Materials for
Various Electronic Applications

A modified version of the computer programme SINC-S is described which permits the user to specify independently
up to 30 different device temperatures in a given problem when the proper control statement is included. An
additional option is an algorithm for the steady-state solution of a non-linear network with periodic inputs, so that
realistic system operation may be simulated. The programme may be used to provide more accurate simulation of
circuits where large temperature gradients are present, and to furnish input data for other thermal analysis
programmes

Carl R. Zimmer

A Computer Programme With Temperature Gradient Capability for the
Network Analysis of Hybrid Circuits

It is only in the last ten years or so that solid state physics has had the temerity to consider that real solids are
neither perfect nor pure, whereas for many years all resistors of reasonable quality have been impure, highly doped,
and clearly disordered in structure. As solid state theory has developed there have been attempts to understand the
resistor problem but until now, with hindsight, we can say that the tools required have not been available. The
situation is, even now, not perfectly clear but there is sufficient information available to make a critical assessment
of the methods that can be applied and to indicate where the solution to the problem of carrier transport in resistor
materials might lie.

Robert M. Hill

Electrical Transport in Thick Film Resistors

Complete testing and high speed automated assembling are the main advantages which are offered by the technology
called Tape Automated Bonding (TAB). The main step in this technology is a bumping of wafers which is usually
performed by the IC manufacturers. When the bumped wafers are not available, the hybrid circuit manufacturers
are forced to bump wafers themselves. As the bumping process consists of several operations requiring many
preliminary steps, a new bumping process which is based on ultrasonic bonding of the preformed gold bumps to the
aluminium pads of chips has been suggested. Compatibility of such bumped chips with TAB and the shear strength
of those bumps were tested.

Karel  Kopejtko

Jind&#345;ich  Vil&#237;m

An Alternative Way of Making Bumps for Tape Automated Bonding

During investigations of failure mechanisms and failure avoidance we have studied the kinetics and the mechanisms
responsible for the growth of the Au-Al compounds. Au4Al, Au5Al2, Au2Al, AuAl, AuAl2 
have been observed and the growth kinetics of the Au2Al, AuAl, AuAl2 follow a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mrow><mml:mrow><mml:mo>(</mml:mo><mml:mrow><mml:mtext>time</mml:mtext></mml:mrow><mml:mo>)</mml:mo></mml:mrow></mml:mrow><mml:mrow><mml:mrow><mml:mn>1</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:mrow></mml:msup></mml:mrow></mml:math> dependence. The activation energy for the
growth of Au2Al is 1 eV and 1.2 eV was found for AuAl and AuAl2. The kind of compound formed depends on
the samples preparation and the results indicate that the kinetics of the mixing is the main mechanism responsible
for the sequence of formation of the various compounds.

E.  Galli

G.  Majni

C.  Nobili

G.  Ottaviani

Gold-Aluminium Intermetallic Compound Formation

The effect of substrate type on the electrical properties of thick film resistors is determined. Five different
substrates are used. The following properties are investigated: &#8211; thermal expansion, resistor profiles, resistance,
TCR and resistor gauge factor. The resistors are physically inspected using X-ray diffractometry and electron
probe analysis. This paper shows that conduction mechanism models for thick-film resistors generally need not
take into account chemical and structural interactions with the substrate. However the effect of substrate on TCR
values is significant for resistors exhibiting a large piezoresistive effect.

A.  Cattaneo

L.  Pirozzi

B.  Morten

M.  Prudenziati

Influence of the Substrate on the Electrical Properties of
Thick-Film Resistors

Thermal print heads are finding widespread application in equipment as diverse as pocket calculators, chart
recorders, and computer page printers. The use of thick film resistors to mark paper is one of the more common
techniques and the design problems and performance available from such heads are the subject of this paper. Future
developments of the technology are also discussed.

Peter  Barnwell

Thick Film Thermal Print Heads

About this journal

Active and Passive Electronic Components provides a forum for the science and technology of all types of electronic components, and publishes experimental and theoretical papers on topics such as transistors, hybrid circuits and sensors.

Journal profile

Meet the editorial board

Active and Passive Electronic Components maintains an Editorial Board of practicing researchers from around the world, to ensure manuscripts are handled by editors who are experts in the field of study.

Editor spotlight

Submit your proposal

Do you think there is an emerging area of research that really needs to be highlighted? Or an existing research area that has been overlooked or would benefit from deeper investigation? Raise the profile of a research area by leading a Special Issue.

Special Issues

Author guidelines

Editorial board

Databases and indexing

Active and Passive Electronic Components | Hindawi

title

Active and Passive Electronic Components provides a forum for the science and technology of all types of electronic components, and publishes experimental and theoretical papers on topics such as transistors, hybrid circuits and sensors.

description

https://images.hindawi.com/journals/apec/apec.banner.jpg

twitter:card

twitter:description

twitter:site

twitter:title

twitter:url

twitter:image

Active and Passive Electronic Components

This Issue is now open for submissions.
Papers are published upon acceptance, regardless of the Special Issue publication date.

Active and Passive Electronic Components

The Second European Hybrid Microelectronics Conference. Part I

The Second European Hybrid Microelectronics Conference. Part I

Articles

An Improved Thick Film Aluminium Conductor Process

Tantalum Thin Film Capacitors With Various Types of Counterelectrodes

Advances in Thick Film Conductors for Microwave Integrated Circuits

New Light-Sensitive Positive-Working Thick Resist Materials for Various Electronic Applications

A Computer Programme With Temperature Gradient Capability for the Network Analysis of Hybrid Circuits

Electrical Transport in Thick Film Resistors

An Alternative Way of Making Bumps for Tape Automated Bonding

Gold-Aluminium Intermetallic Compound Formation

Influence of the Substrate on the Electrical Properties of Thick-Film Resistors

Thick Film Thermal Print Heads