Plastic Materials for Microelectronics

Course Overview
Course Outline
Past Customers
Related Texts


Course Overview

A plastic-encapsulated microelectronics (PEM) component, often called a plastic package, consists of an integrated circuit chip physically attached to a leadframe, electrically interconnected to input-output leads, and molded in a plastic that is in direct contact with the chip, leadframe, and interconnects. In comparison, a hermetically sealed microcircuit (generally called a hermetic package) consists of an integrated circuit chip mounted in a metal or ceramic cavity, interconnected to the leads, and hermetically sealed to maintain a contact environment within the package.

Historically, PEMs have been used in commercial and telecommunications electronics and consequently have a large manufacturing base. With major advantages in cost, size, weight, performance, and availability, plastic packages have attracted 97% of the market share of worldwide microcircuit sales, although they encountered formidable challenges in gaining acceptance for use in government and military applications. In fact, it was only in the early 1990s that the industry dispelled the notion that hermetic packages were superior in reliability to plastic packages, in spite of their low production and procurement volumes and the outdated government and defense department standards and handbooks associated with their manufacture and use. Today, high-quality, high-reliability, high-performance, and low-cost plastic-encapsulated microcircuits are common. Thanks to new packaging materials, improved design, increased reliability testing, and other important developments, PEMs are not, in many cases, the most cost-effective option for a wide range of electronic systems applications.



Course Outline

1. The Changing World

  • Device and package construction and fabrication
  • The first encapsulated devices
  • Device and package classification
  • Worldwide market trends
  • Technology trends
  • Reliability trends
  • Status of QML
  • The use of encapsulated microcircuits in high-reliability applications
  • Hurdles to PEM insertion
  • Missed and potential opportunities

2 .Plastic Parts Technology

  • Materials, fabrication processes, and quality
    • Overview of the PEM constituents
    • Die passivation
    • Leadframes
    • Die attaches
    • Wire bonding
    • Other interconnects
  • Molding compound materials
    • Resins
    • Filler materials
    • Cross-linking materials
    • Accelerators
    • Flame retardants
    • Flexibilizers
    • Other molding compound constituents
    • Molding compound qualification
  • Package assembly
    • Transfer molding: process and equipment associated problems
    • Post cure
    • Deflash
    • Trim and form

3. Handling and PWB Assembly Issues

  • Packing and handling
    • Requirements
    • Package containers, shipping boxes, and materials
    • Moisture sensitivity and protection from moisture
    • ESD protection
  • Assembly with plastic encapsulated microcircuits
    • Assembly technologies
    • Soldering processes
    • Soldering defects
    • Failures during assembly
    • Cleaning and conformal coating

4. Quality, Integrity and Application-Specific Reliability

  • Results of commercial insertion studies
    • CALCE-ELDEC parametric reliability test program
    • French ministry of defense HAST study
    • DLA parts availability program
    • Texas Instruments studies
    • Johns Hopkins F/A-18 study
    • Naval Weapons Center-China Lake study
    • Long term dormant storage in commercial distributor warehouse
    • Long term dormant storage in re-manufacturing center
    • Long term dormant storage of PEM assemblies in military field environments
    • Commercial insertion into fast jet avionics - several studies
    • NASA and National Semiconductor space environmental studies
    • Intermittent use of automotive engine control module
    • Field failure return studies
  • Moisture ingress and contaminants
    • Failure mechanisms in PEMs associated with moisture and ions
    • Effects of molding compound on moisture diffusion
    • Effects of environment on moisture diffusion
    • Ion diffusion in molding compounds
    • Effect of encapsulant material and its constituents on ion diffusion
    • Limitations of HAST in determining effects of contaminants
  • Reliability assessment methodologies and tools
    • Reliability assessment and qualification
    • Problems with burn-in
    • Screening guidelines
    • PEM reliability models and their validity
    • Physics-of-failure reliability modeling
    • Software for reliability assessment, testing and screening
  •      Failure analysis techniques
    • Why failure analysis
    • Failure analysis procedure
    • Optical analysis
    • Mechanical analysis
    • Electron microscopy and its variations
    • Selection of failures analysis techniques


Past Customers

  • AlliedSignal - Arizona
  • Hazeltine Co. - New York
  • Lockheed-Martin - Utah
  • Lucas Aerospace - United Kingdom
  • M/ACom - Massachusetts
  • Motorola - Illinois
  • Sandia National Lab - New Mexico
  • StorageTek - Colorado
  • Sverdrup Technology, Inc. - Florida


Related Links and Texts



Michael Pecht
Bldg. 89, Rm. 1103
University of Maryland
College Park, MD 20742


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