Electronics packaging

TWI has been actively involved in electronic packaging for over 40 years. Work has covered all aspects of chip attachment (adhesives, soldering, glass, mechanical etc), interconnection (flip chip, TAB, wire bonding, adhesives etc), encapsulation (glob top, potting, plastic moulding), hermetic sealing (soldering, brazing, welding, glass fusion) and substrate/board assembly.

PCB board

Additional key elements of TWI's work include: product design/modelling, quality assessment/control, testing (e.g. mechanical, thermal and environmental), manufacturability and troubleshooting. A large number of projects have been performed by TWI for industrial members both singly and collectively. Find out more about the processes by looking at the Knowledge Summaries and Best Practice Guides. The outcome of a significant amount of work performed at TWI is given in a number of published papers and reports.

TWI also runs a number of Standard and Tailored Training Courses.

A number of the processes in which TWI has experience are shown in the following video clips. Click on the thumbnail image to download the video clip. To view these video clips you need an MPEG-1 Video Player. If you have difficulty with this, please talk to an experienced web user.

TWI's Photographic and Video department offer a wide range of photographic, video and multimedia services.

Wire bonding see it in action 13842kB	Tape automated bonding see it in action 6328kB
Die attach see it in action 4417kB	Laser welding see it in action 4065kB

Projects performed in the Electronic Packaging area

The Core Research Programme (CRP). Member companies have free access to these generic R&D projects. The work forms the basis of TWI's multi-million pound funded programme of industrially aligned research. The projects relevant to the Electronic Packaging area are given below.

Development of accelerated product-life test methods for electronics products
Development of low volume rapid dispensing/cure adhesive system for optoelectronics & sensors
Development of packaging methods for high temperature electronics
Chemical coatings
Joining of oxide ceramics
High speed, wavelength dependent processes for plastics design data for avoiding premature failure in plastic welds
Design data for avoiding premature failure in plastic welds
Modelling of welds in polymers
Development of the ClearWeld ^TM

Group Sponsored Projects (GSPs). These R&D projects are funded by a number of member companies, usually to address the medium term needs within a particular industrial sector. Results of the work are only available to the group of participating sponsors. The projects relevant to the Electronic Packaging area are given below.

Projects being formed

High speed adhesive manufacturing technology for the precision placement of optical elements.

Single Client Projects (SCPs). TWI conducts several hundred of these strictly confidential projects per year. The following list gives an indication of the types of projects undertaken. The Case Studies, which have all been cleared with the sponsoring companies, give further details.

Development of Cu wire ball bonding
Development of flip chip stud bumping technology
Assessment of flip chip bonding techniques
Development and verification of high thermal conductivity die attach techniques
Development of a large area die rework station
Assessment of conductive adhesives for SMT and space environments
Packaging technologies for the display/sensor industry
Performance of resin encapsulants/potting materials
Low stress hermetic sealing technology
Miniaturised electronics/sensors for medical implants
EMI shielding for discrete devices
Wettability of Pb-free solder
Fine pitch soldering technology
Environmental audit of electronic control system
Verification of thermal modelling software through IR measurements of power devices
Sealing of Al-SiC MMC packages
Ultrasonic Welding Of Thermoplastics Encapsulated Electronics Case Study
Wire/Ribbon Tape Automated Bonding Case Study
Ribbon Bonding For Device Interconnection Case Study
Microfocus inspection system is a winner Case Study

Facilities for conducting this work are based at the Microtechnology & Reliability Centre in Cambridge and a new PCB Assembly Centre in Middlesbrough.

Postgraduate Training Partnership (PTP) work ongoing which is relevant to the Electronic Packaging area

Modelling the reliability of lead free solder joints
Ceramic reinforced active metal braze alloys
Characterisation of interfaces formed in solid state bonding of dissimilar materials
Fabrication of phosphate matrix composites
Mechanical properties of laser welds in polymers
Long term durability of adhesive joints
Improved high temperature brazed ceramic to metal joint

Related Knowledge Summaries

Related Best Practice Guides

Soldering Materials and Design
Soldering Processes
Soldering Process Control
Adhesive Bonding - a guide to best practice
Joining Ceramics - a guide to best practice
Thermal Spraying - a guide to best practice

TWI Published papers and reports related to the Electronic Packaging area

Smith L S and Threadgill P L: 'Magnesium joining - new developments aid industrial fabrication ', Connect, no.109. Nov.-Dec.2000. p.3

Cole C E, Noden S C, Tyrer J R and Hilton P A: 'The application of diffractive optical elements in high power laser material processing', Laser Materials Processing. Proceedings, Conference, ICALEO '98, Orlando, Florida, 16-19 Nov.1998

Dickerson T: 'Measurements of the stress-strain behaviour of three die attach materials and the material influence on die failure', Micro Materials. Proceedings, International Conference and Exhibition, Micro Mat '97, Berlin, 16-18 Apr.1997, ISBN 3-932434-05-6, pp.275-278

'Developments in Microjoining 1970-1983', Abington Publishing, 1983.

Stockham N R and Dawes C J: 'Resistance seam & laser welding of large hybrid metal packages', International Journal for Hybrid Microelectronics, Vol. 6, No. 1, Oct 1983, pp509-519.

Taylor G M: 'Wire bonding for small electronic contact pads', TWI Research Bulletin Vol. 21, No. 9, Sept 1980, pp260-264.

Dawes C J: 'Ultrasonic ball/wedge bonding of aluminium wires', TWI Research Bulletin, Vol. 20, No. 1, Jan 1979, pp9-14

Brazing of heat sink attachments for new electronic ceramic substrates, Hanson, Fernie & Stockham

Stockham N R: 'Joining techniques for fine pitch surface mount devices', High Performance Electronic Packaging Proceedings, 28-30 Nov 1990, Paper 26, pp 58-67.

EUREKA project EU462 PEPITE Europe's leading-edge in advanced electronics, EUREKA secretariat, 1993

S M Stevens: 'Fourier transform infrared spectrometry for the analysis of polymers', TWI Bulletin, Vol. 29, No. 5, Sept/Oct 1988, pp 210-213.

White G L: 'An introduction to die attach', TWI Bulletin, Vol. 26, No. 8, August 1985, pp 268-271.

Fernie J A: 'Techniques for bonding ceramics', TWI Bulletin Vol. 31 No. 9/10, Sept/Oct 90, pp 92-93.

Harvey D: 'HVOF takes off', TWI Bulletin, Vol. 32, No. 5, Sept/Oct 91, pp107-109.

McGrath G M: 'Not sticking to a tradition - a guide to adhesive bonding', TWI Bulletin Vol. 32, No. 3, May/June 91, pp 64-67.

Sturgeon A: 'Ceramic coatings - a growing technology', TWI Bulletin, Vol. 33, No. 2, March/April 1992, pp 31-35.

Tavakoli S M: 'Adhesive joints - how strong, how long?', TWI Bulletin, Vol. 34, No. 2, March/April 93, pp 40-42.

Saunders D: 'Preparing for adhesive bonding', TWI Bulletin, Vol. 35, No.3, May/June 94, pp 60-62.

Sturgeon A: 'Thermal spraying gives a new look to substrate design', TWI Bulletin, Vol. 35, No.4, July/Aug 94, pp 84-87.

Sturgeon A: 'Alumina coatings - HVOF using hydrogen', TWI Bulletin, Vol. 35, No. 6, Nov/Dec 94, pp 136-138.

Taylor A: 'Sol-gel: synthesising glasses and ceramics', TWI Bulletin, Vol. 137, No. 2, March/April 96, pp 32-34.