Latest IPC Roadmap for Interconnect Technology Released
Eric Bogatin, Contributing Editor -- Semiconductor International, 4/1/2003
"To establish and maintain leadership in electronic interconnect technology" is the purpose of the 2002/2003 IPC roadmap, released this month, according to key contributor Jack Fisher. The IPC roadmap is one of three important U.S. electronics industry roadmaps, along with the National Electronics Manufacturing Initiative (NEMI) for OEMs and the International Technology Roadmap for Semiconductors (ITRS) for semiconductor technology.
The IPC was first created in 1957 as the Institute for Printed Circuits. Today, the meaning of the initials has been dropped, and the official name IPC is accompanied by the subtitle "Association Connecting Electronics Industries." It is the largest industry association covering printed circuit board (PCB) fabrication, design and assembly, and all related infrastructure issues. One of its important functions is the creation and publication of industrywide specifications for the design and assembly of PCBs and components that are assembled on them.
Every decade has a different set of products acting as a primary technology driver. The roadmap's authors have suggested that it was mainframes that drove the '60s and '70s, followed by personal computers in the '70s and '80s and hand-helds in the '80s and '90s. Throughout the '90s and today, it is high-speed data and rf, and the authors believe that future technology might be driven by optoelectronic needs.
One of the important paradigm shifts they identified is the leading role backplanes are beginning to play. In the past, backplanes used existing PCB technology. Now, with the demand for higher transmission speed, they are driving new laminate materials, especially lower-loss dielectrics.
The roadmap offers a snapshot view of the current state of worldwide PCB manufacturing capability, and the expectations for the near future. The Table summarizes the current standards for conductor width, plated hole diameter and microvia diameter, for example.
Status of PCB Industry | |||
Attribute | Conventional | Leading edge | State of the art |
Conductor width and space (min. in µm) | 125 | 75 | 50 |
Plated through-hole diameter (min. in µm) | 250 | 200 | 150 |
Microvia diameter (min. in µm) | NA | 100 | 75 |
High-density interconnect (HDI) technology continues to be an important technology. However, surprisingly, all volume production is with one to two layers only. There is very little use of three to four layers of HDI with microvias.
Two new terms have been introduced in this edition of the roadmap. The first is JISSO. Michio Tanimoto, chairperson of the Electronic Systems Integration Technical Committee of the EIAJ (Electronic Industries Association of Japan), used JISSO to refer to "system integration: electronic packaging." He defined it as "technology that forms a system for highly integrated design of electronic systems and interconnections of device subsystems." In this view, all interconnects from redistribution layers on a wafer to the cables between racks of equipment are part of JISSO technology.
In 1999, EIAJ published the Japan JISSO Technology Roadmap (http://216.203.210.37/David/IPC.pdf), formalizing this term to refer to the system integration view of packaging and interconnect technology. JISSO technology will become the generic term referring to the entire packaging and interconnect hierarchy, and particularly the desire for system optimization rather than component sub-optimization.
The second new term introduced by the IPC roadmap is multi-device subassembly (MDS). The proposed definition is "a subsystem which consists of multiple electronic devices including at least one integrated circuit." This term is supposed to take the place of other commonly used terms such as hybrid IC, MCM, MCP, FCM, FCP, SiP, SIMM and DIMM. The key feature of an MDS is that it interfaces to a circuit board like any other single-chip package, so its handling, testing, shipping and assembly issues are identical to the infrastructure of single-chip packages. This new term will hopefully focus attenuation on the interface between users and suppliers, rather than the specifics of what's inside the component, which could be a single IC, a stacked chip or chips and passives.
It is impossible to generalize what the "best" technologies might be because every product application has a different set of driving forces. The IPC roadmap provides a framework of eight product form factors as a partitioning of the entire end-user market. These represent the major product groups in the industry today: portable electronic games, under $500 consumer products, hand-held/wireless, mid-range performance electronics (office systems), high-performance systems (mainframes/mass storage), rf and microwave electronics, aerospace and automotive electronics.
Perhaps the final conclusion from the roadmap is a generalization that applies as a whole to the packaging industry: "Nothing ever goes away, e.g. the rumored death of through hole has been greatly exaggerated."
For additional information on assembly and packaging, go to www.semiconductor.net/assembly
