DFM for Flex and Rigid-Flex PCBs Utilizing SMT

Vern Solberg

SMT Technical Consultant

In this webinar

Developing a flexible circuit for surface mount component assembly entails a unique set of requirements. To quote a leading flexible circuit fabricator “Understanding how these requirements interact will allow the PCB designer to create a flex circuit that balances both electrical and mechanical features into a reliable, cost effective interconnect solution”. There are a broad number of reasons for developing the flexible and rigid-flex circuit;

• Increased wiring density- flexible circuits are capable of providing very narrow
conductors requiring only 25% of the space typically reserved for hard-wire
interconnect.

• SMT component interconnect- Land pattern features can be incorporated within the
flexible circuit pattern to accommodate the mounting and interconnecting both
passive and active surface mount components.

• Mechanical compliance- the thin base material is not only flexible but can be
shaped to fit unique and often complex 3D interconnect applications and enables
the inclusion of rigid materials when greater physical support is warranted.

Topics of discussion:

1. DfM principles for flexible and rigid-flex circuits

Establishing flex circuit construction types

Base materials for flexible and rigid flex

Cover coating and film variations

Conductor routing and physical feature planning

Flexible circuit bending and folding guidelines

EMI shielding and impedance control methodology

2. SMT component selection and land pattern development

Passive R and C devices

SOICs

QFN and QFP

BGA and CSP

3. DfM for SMT assembly processing

SMT assembly process overview
Preparation for SMT assembly
Land pattern reinforcement
Conductor to land interface
SMT component area support

About Vern Solberg

Vern Solberg is a Technical Consultant specializing in surface mount technology and microelectronics. He has served the industry for more than thirty years in areas related to both commercial and aerospace electronic product development and holds several US patents for 3D semiconductor packaging innovations. Mr. Solberg is currently a working member of the IPC, the electronic industries primary standards development organization.

During his career Mr. Solberg has authored a broad range of technical papers and publications on microelectronics including two books focusing on ‘Design Guidelines for Surface Mount and Fine-Pitch Technology’ published by McGraw-Hill. He is also the recipient of the ‘Surface Mount Technology Association (SMTA) Founders Award’, the ‘IPC Presidents Award’ and the prestigious ‘Raymond E. Pritchard Hall of Fame Award’.

In addition to supporting the education activities for a wide range of technical conferences in North America, Australia and Asia, Vern has served as an instructor for PCB Design for Surface Mount Technology at the University of Wisconsin School of Engineering in Milwaukee and conducted a series of training workshops for students and faculty members at Kansas State Universities’ Microelectronics Laboratories in Salina.