A flexible circuit is more than just thin materials made into an interconnecting device. Understanding the characteristics of the materials and their properties versus circuit design type and requirements,are variables that circuit designers and fabricators should understand in order to build the best performing and cost effective alternatives for their customers. Sometimes the requirements of a design are only vaguely identified and the information requested from a materials supplier is not always the most applicable for the desired design and application. Over or under performance is designed in,requiring several iterations of building and testing to get to the most desired cost effective end result. Prototyping with one material type and then going to production with another material type also is cause of concern for the end user. Not all materials are the same,even when they are “generically” lump ed into groups for convenience sake.

Two emerging board technologies,embedded passives and embedded optical waveguides,have the potential to change the way that printed wiring boards operate. No longer will interconnects be relegated to copper,but true passive electrical functionality will be incorporated into the board. Some high speed electrical interconnects may actually be replaced with pulses of light guided through transparent optical materials built into the board. These technologies are reviewed in simplified form,and the implications for board designers are examined.

Embedding resistors right into the printed circuit board substrate is not new,but it is gaining momentum as a rapidly
emerging and pivotal technology for the PCB industry,perhaps preceded only by the plated thru hole in the 50s and
microvias in the 80s. Embedding resistors requires designing resistors. Designing resistors requires understanding the resistor manufacturing process. Resistor materials are available in a wide range of values and technologies. This paper is written from a design for manufacturing perspective and includes guidelines for designing resistors with commercially available materials and manufacturing technologies to embed directly into the PCB substrate.

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As IC technology advances,electronic packaging for the ICs has had to advance as well. The package methodology has become technically more sophisticated and physically more complex. For many IC package applications,the lead-frame package technology of the past is not adequate. The Ball Grid Array (BGA) and Chip-Scale Package (CSP),on the other hand,are seen by many as the most viable solution for improving both functionality and performance. Array package technology is well established in the industry and the market growth for the BGA families has exceeded forecast. The array package technology and methodology has evolved throughout the past decade and many of the newer generations of BGA and CSP devices have become smaller and adapted finer contact pitch than their predecessors. The finer contact pitch BGA package enables the IC manufacture to meet the demand for higher I/O need for the mo re complex applications while maintaining a relatively small package outline. By adapting a finer contact pitch,however,can dramatically affect the methodology used in board design and assembly. Because of the higher contact density made possible by array type packaging,design specialists have realized that the higher density land pattern geometry significantly effects PC board routing efficiency and can definitely impact fabrication cost. When adapting BGA and chip-scale BGA packaging in particular,one must consider board fabrication tolerances and provide the necessary physical features needed for assembly machine processing. For assembly process control,land pattern geometry is of primary concern because it is directly related to solder attachment uniformity. This paper will review BGA/CSP applications,packaging standards and package assembly methodology,furnish circuit routing guidelines for array packaged devices and review recommendations for design defined in IPC-7095A,the Standard Guideline for Design and Assembly Process Implementation for BGAs.

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With the advent of CAD and CAM tools,the need arose for a more complete method of data transfer. As layer count
increased,the number of files increased. As trace size and spacing began to decrease,the Gerber file size increased. The need
for a better method of Data Transfer was recognized. The search for the Data Transfer Solution began.
IPC develop the GenCAM Initiative with a program to address the Data Transfer Solutions (DTS) with DTS ’97,DTS’98,
DTS’99,DTS’00,DTS ’01,DTS ’02… The idea behind the DTS was to parse large data files into an ASCII formatted,
process oriented segmented file. At the same time,Valor was developing the ODB+ format for its tools. And the industry
used Gerber because it was okay.

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The migration to Lead Free raw materials in the Electronics Industry will happen faster than the date proposed in the original
draft of the legislation. A true Pb-free solution for product such as high end and volume server and desktop requires printed
circuit boards and electronic packages to be totally free of lead and compatible with the higher processing temperatures.
Raw materials such as solder paste are under stringent characteristic assessment to fulfill optimal solder joint quality and
reliability in mechanical strength and lower ionic and organic residue contamination. Characteristics such as printability,
stencil life & cleaning,tackiness,slump,viscosity,wetting,solderability,copper mirror corrosion,thermal optimization,
SIR/EM,ionic and organic contamination etc of both no-clean and aqueous solder pastes will be studied.

The Lead-free electronics manufacturing has become a reality. As of this writing,a few manufacturers have rightfully
reported their total completion to Lead-free production across all facilities,and some have reached partial implementation.
This paper focuses on replacing63Sn37Pb (or its equivalent) solder joint material and crucial manufacturing practices without
using a higher process temperature. The paper also presents some exemplary real-world production results of the drop-in
manufacturing by using the properly selected Lead-free solder alloys that are able to perform as a direct replacement for
63Sn37Pb solder joint material. Based on the 14-year systematic and sustained study of Lead-free solder materials in
conjunction with the 23-year SMT manufacturing establishment,the fundamental material properties and mechanical
behavior of the drop-in materials in relation to production and reliability will also be briefly summarized.