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IMAPS PDC Webinar Series on
Rheology Issues in Electronic Packaging

This three-session on-line Professional Development Course (PDC) webinar was held:
Tuesdays, November 16, 23 and 30, 2010

All webinars were held 12:00 noon - 1:00 pm EST

IMAPS Members: $125 per webinar; 3-course series $250
Non-members: $200 per webinar; 3-course series $500

Registration Deadlines: November 15, 2010

Key Words/Topics

Rheology, polymers, thermosets, thermosetting polymers, adhesives, coatings, mold compounds, die attach, rheology during curing, chemorheology of epoxy curing, epoxies, dielectric cure monitoring

Program Description

These 3 one-hour PDC lectures can be taken in total or separately, but to gain the most benefit it is recommended to attend the whole series in order. Each session is scheduled for 50 minutes of presentation followed by 10 minutes of Questions and Answers. A brief description of each session follows:

Session 1 of 3: Tuesday, November 16 -- 12:00-1:00 PM EST

Introduction to Rheology
This session will provide a broad overview of the basic concepts of rheological properties and types of instrumentation for rheological measurements. Topics to be covered:

  • Why Rheology is important
  • Basic rheological definitions (viscosity, shear stress, shear rate, moduli)
  • Types of rheological measurements
  • Examples of typical rheological properties of polymers  

Session 2 of 3: Tuesday, November 23 -- 12:00-1:00 PM EST

Rheology in Semiconductor Packaging
This session will build on the previous webinar and cover some key rheological considerations governing the performance of polymer-based materials used in packaging semiconductors. In most cases, adhesives, underfills, mold compounds and coatings are applied as viscous liquids and then cured. The flow properties are critical to performance in high volume manufacturing. This session will cover the basics in:
  • Introduction to the rheological properties of adhesives (shear thinning, viscosity, time dependence, rheology changes during curing)
  • Rheology of Capillary Underfills
  • Encapsulants (mold compounds) and coatings

Session 3 of 3: Tuesday, November 30 -- 12:00-1:00 PM EST

Rheological Considerations in Substrate and Printed Circuit Board Fabrication
Semiconductor substrates and printed circuit boards are complex composites typically manufactured using a lamination process. Cores with circuit features are laminated with prepregs (B-staged, partially cured glass cloth composites) to form multilayer structures. The lamination process involves both chemical and viscoelastic property changes during lamination. The session will cover:

  • Chemorheology during curing
  • Concept of the rheological flow window
  • Gelation and vitrification during curing and the impact on flow
  • Overview of dielectric cure monitoring for in-situ measurement of the rheology and curing process

Who Should Attend?

Packaging engineers involved in the development, production, and reliability testing of semiconductor packages would benefit from the series. Those interested in gaining a basic understanding of the role of polymers and polymer-based materials used in electronic packaging will also find this series valuable.

Thomas Green


Dr. Jeff Gotro has over twenty-six years experience in polymers for electronic applications and composites having held scientific and leadership positions at IBM, AlliedSignal, Honeywell, and Ablestik Laboratories. He is an accomplished technology professional with demonstrated success directing new product development, leading to multi-million dollar revenues. He has global experience developing new products having established a full function R&D and Applications Engineering lab in Shanghai, China for Ablestik Laboratories. Jeff has consulting experience with companies ranging from early-stage start-ups to Fortune 50 companies.

Jeff is a nationally recognized authority in thermosetting polymers and he has received invitations to speak at prestigious Gordon Research Conferences (Thermosetting Polymers and Composites). He has presented numerous lectures and short courses at national technical conferences.   Jeff was an Adjunct Professor at Syracuse University in the Dept. of Chemical Engineering and Materials Science from 1986-1993.  He taught Six Sigma Black Belt and Green Belt at California State University at Fullerton from 2001-2006, and teaches courses on Innovation and Product Development in the MBA program at Concordia University in Irvine, CA. 

Jeff is a member of the Product Development and Management Association (PDMA), American Chemical Society (ACS), the Institute for Management Consultants (IMC), the Forensic Expert Witness Association (FEWA), and the International Microelectronics and Packaging Society (IMAPS).

Jeff has published 60 technical papers (including 4 book chapters) in the field of polymeric materials for advanced electronic packaging applications, holds 13 issued US patents, and has 7 patents pending. 

Jeff has a Ph.D. in Materials Science from Northwestern University with a specialty in polymer science and a B.S. in Mechanical Engineering/Materials Science from Marquette University.

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