Fine Pitch Surface Mount Technology

Fine pitch high lead count integrated circuit packages represent a dramatic change from the conventional methods of assembling electronic components to a printed interconnect circuit board. To some, these FPTpackages appear to bean extension of the assembly technology called surface mount or SMT. Many of us who have spent a significant amount of time developing the process and design techniques for these fine pitchpackages haveconcluded that these techniquesgobeyondthose commonly useed for SMT. In 1987 the presentauthor, convincedofthe uniqueness ofthe assembly and design demands ofthese packages, chaired ajoint committee where the members agreed to use fine pitch technology (FPT) as the defining term for these demands. The committee was unique in several ways, one being that it was the first time three U. S. standards organizations, the IPC (Lincolnwood, IL), theEIA(Washington, D. C. ),and theASTM (Philadelphia),cametogether tocreate standards before a technology was in high demand. The term fine pitch technology and its acronym FPT have since become widely accepted in the electronics industry. The knowledge of the terms and demands of FPT currently exceed the usage of FPT packaged components, but this is changing rapidly because of the size, performance, and cost savings of FPT. I have resisted several past invitations to write other technical texts. However, I feel there are important advantages and significant difficulties to be encountered with FPT.

Springer Book Archives

1 Introduction to Fine Pitch Technology (FPT).- 1.0 Introduction.- 1.1 What is Fpt?.- 1.2 The Benefits of Fine Pitch Technology.- 1.3 The Motivation for Fine Pitch Technology.- 1.4 Comparison of Fpt with Through-Hole and Surfacemount Technologies.- 1.5 Fine Pitch Technology Obstacles and Issues.- 2 The Family of FPT Packages.- 2.0 The Evolution of Fpt Packages.- 2.1 Introduction and Construction of Fine Pitch Packages.- 2.2 Quad Flat Packages.- 2.3 Plastic Quad Flat Packages.- 2.4 Small Outline Packages.- 2.5 Tape Automated Bonded and Guard Ring Packages.- 2.6 Package Handling and Shipping.- 2.7 Package Reliability and Quality.- 2.8 Issues When Selecting an Fpt Package.- 3 Fine Pitch Product Applications.- 3.0 Applications.- 3.1 Product Applications.- 3.2 Package Usage.- 4 Printed Circuit Boards for Fine Pitch Technology.- 4.0 Basic Pcb Processing.- 4.1 Material Options and Properties.- 4.2 Fabrication and Assembly Issues.- 4.3 Composite Electrical Properties.- 4.4 Composite Thermal Properties.- 5 Solder and Application Methods.- 5.0 Solder.- 5.1 Solder Alloy Choices.- 5.2 Flux.- 5.3 Solvents and Thixotropes.- 5.4 Specifying a Paste.- 5.5 Storage.- 5.6 Paste Quality Control and Testing.- 5.7 Applying Solder Paste.- 6 Package Placement.- 6.0 Placement.- 6.1 Placement Options.- 6.2 Additional Placement System Features.- 6.3 Throughput Requirements.- 7 Solder Reflow.- 7.0 Reflow Defined.- 7.1 The Dynamics of the Reflow Process.- 7.2 The Heat Source.- 7.3 Selecting a Reflow Method.- 7.4 Changing Component Location During Reflow.- 8 Post Reflow Cleaning.- 8.1 Successful No-Clean.- 9 Inspection, Rework, and Repair.- 9.0 Inspection.- 9.1 Rework and Repair.- 10 Design for Reliability Guidelines.- 10.1 Defining Solder Joint Reliability.- 10.3 Cause of Solder Joint Fatigue.- 10.4Solder Joint Prediction Models.- 10.5 Electronic Product Use Conditions.- 10.6 General Design for Reliability Guidelines.- 11 Design for Testability.- 11.0 Basics of Electrical Testing Pcas.- 11.1 Contacting the Assembly.- 11.2 Disadvantages of In-Circuit Testing.- 11.3 Alternatives to In-Circuit Testing.- 11.4 Successfully Using Ict For Fpt Testing.- 12 Design for Manufacturability.- 12.0 General Dfm Guidelines.- 12.1 The Rules of Dfm.- 12.2 Implementing Dfm.- 12.3 Dfm Summary.- 13 Specific Design Guidelines for FPT Packages.- 13.1 Package Selection.- 13.2 Package Placement on the Board.- 13.3 Land Pattern Size.- 13.4 Trace Routing and Protection.- 13.5 Thermal Management.- 13.6 Fabrication of the Board.- 13.7 Stencil Fabrication.- Appendix A Addresses of Standards Organizations.- Appendix B Summary of SMT Semiconductor Outlines from JEDEC Publication 95.- Appendix C Summary of Important Component, Material,Process and Design Standards.