In the printed circuit board industry there are generally two main types of circuit boards; there are rigid printed circuit boards and flexible printed circuit boards. There is a tremendous variety of these general types; however the industries that
specialize in one type may have some weakness in understanding some issues related to the other type. Specifically,the flexible circuit industry has come to understand bending,forming and dynamic flexing motion of circuits. The rigid circuit board industry typically will not understand these issues as well. Those who work in the rigid board circuit industry are typically those who fabricate the High Frequency circuit boards. Due to this,there have been several issues with bending,forming and flexing high frequency circuit boards.
All types of circuit boards have the same basic theory for bending,forming and flexing. However the circuit board construction and the materials used,will limit which type of board can feasibly be bent,formed or flexed. Normally woven
glass reinforced circuit boards cannot be bent,formed or flexed reliably. There are many different types of materials used for fabricating high frequency circuit boards and there are several that are non-glass woven reinforced. This paper will address
bending,forming and flexing circuits built with non-glass woven circuit materials.

Oxide alternatives,as well as traditional and reduced oxide chemistries,are coatings or “adhesion promoters” used to enhance the bond between imaged and etched inner layer copper surfaces and the pre-preg resin used to bond the layers together in multi-layer printed circuit boards (PCBs). These chemistries impart varying degrees of roughness to the surface of the copper conductors and as a result electrical performance can be affected. The electrical performance characteristics of two oxide alternatives are examined in this study.

The RoHS legislation in Europe has far reaching consequences,which necessitates a change in lead coating on component leads. Although some suppliers are using a tin finish,there is a tendency for pure tin plating to form whiskers over time which can cause failure of the circuit. To prevent the formation of whiskers different companies have designed different plating schemes and used different materials. Industry has yet to standardize on a lead finish to replace the Sn:Pb solder used in the past.
This paper examines several different lead materials before and after exposure to tin whisker promoting environments to determine the effects of those environments on the soldered connection. In addition to promoting the growth of tin whiskers,these stressful environments also age the solder connections. Based on components used in the telecom industry,solder connections are examined for the presence of tin whiskers,grain structure,intermetallic formation and cracking after being temperature cycled (-40C to 85C) and soaked at 50C and 85% RH.

The whisker concern has been greatly affecting lead free RoHS conversion confidence in the lead frame packages,particularly for high end product conversion. Although plenty of related study in E4 and iNEMI have directed standard whisker testing conditions and measurement methods,the practical whisker performance data in service life is still very small due to numerous extra factors involved from surface mounting and waving soldering.
Most of the literature on Tin (Sn) whiskers study are test results based at the component level in storage or reflow preconditioning to simulate backward and forward conversion in service life. However,for practical Sn-whisker issues,it is
necessary to consider the entire structure,i.e.,the component characteristics,solder joint,PCB and process effect. In this study,matt Sn plated packages with Cu and Alloy 42 based in PLCC,PDIP,LQFP and TSOP were subject to lead free
surface mounting and wave soldering on PCBs with OSP surface finish,followed by TCT (-55 to 85?) 1000 cycle,THT (60?/90%RH) 3000hrs and ambient condition 3000hrs to investigate whisker growth propensity. Whisker growth on the PCB after reflow simulation and separate from the component level was examined to understand whether the whisker risk will be reduced or raised because of factors such as the matt Sn structure,lead frame base,reflow profile and solder paste wetting behavior. Furthermore,SnPb and SnBi plated 4 types of the same package types as above were used as controls for whisker growth comparison. Additionally,corrosion phenomenon due to higher temperature THT testing to correlate to whisker growth after the surface mounting condition will be explored with FIB analysis as well.

Transitioning to offshore sourcing has become a seductive argument for cost reduction. Most managers agree that the impact has been beneficial to the consumer and the trading conglomerates. This paper addresses public perceptions,structural issues,geopolitical and demographic factors that fuel the offshore sourcing argument. It addresses design,marketing,sourcing,and
logistics,local and cultural idiosyncrasies of offshore sourcing that assures a successful venture.

Copyright,like all other forms of intellectual property,is based on negative rights. A copyright registrant may exclude others from reproducing a given copyrighted work,composing a derivative work,performing the work publicly,distributing the work (including sale,lease,or rental of the work),or displaying the work. Works that may be protected by copyright include literary works; musical works and accompanying words; audiovisual works,including motion pictures; sculptural works; pictorial,graphic and architectural works; sound recordings; and,pantomimes and audiovisual works.
The power of copyright is especially effective in preventing the rote copying of a work. A work is a fixed,complete form of authorship. To be complete,a work must have all of its component parts. A computer program which does not run and has no utility is a good example of an incomplete project that is not a work. Direct copying is the easiest form of copyright infringement activity to prevent. However,the test in copyright is one of substantial similarity. Whether a copied work is substantially similar to the copyrighted work is a question of fact to be decided by a jury.

The challenge manufactures face when competing in the world marketplace is to offer a product that will meet all performance and functionality expectations without increasing product size or cost. Increased electronic functionality can be
achieved through the development of more complex silicon integration but that route generally requires a great deal of capital resources and an excessive amount of time. Multiple-die package concepts are often proving superior to the system-on-chip alternative because it minimizes risk and has the potential for economically integrating several different but complementary functions. The information presented in this paper will review several existing package-on-package configurations and introduce a new substrate fabrication process developed to improve IC package density and circuit routing efficiency. In
addition,the basic package assembly methodology will be described and examples of high density stacked memory and mixed function variations shown. In keeping with IPC presentation guidelines it should be noted that a portion of the technical information presented focuses on unique fabrication processes developed for the substrate and are a licensed technology covered by several US and foreign patents.

In this paper,factors that influence the ability for a flex circuit,especially a multilayer flex circuit,to survive the lead-free soldering and other thermal processes during the circuit fabrication processes will be discussed. Results and discussion will be given to demonstrate that the main factors that determine the robustness of a multilayer flex circuit to survive lead-free soldering include: (a) the intrinsic thermal stability of the flex circuit materials used to build the circuit; (b) the multilayer construction of the circuit and related processes making it; and (c) the design of the circuit patterns.

We present the electrical characterization of our Liquid Crystal Polymer (LCP) at microwave and millimeter frequencies and the applications of LCP to circuit components. We use several methodologies to determine the electrical characteristics of LCP for microwave and millimeter wave frequencies. Cavity resonators [1],micro strip T-resonators [2],and micro strip ring resonators [1,3] are measured in order to characterize both the dielectric constant and loss tangent up to 40GHz. The measured dielectric constant is shown to be steady near 3.0,and the loss tangent stays below 0.002,which is better than
advanced polyimide materials. Furthermore,micro strip lines are designed and fabricated on both LCP substrate and other conventional materials in order to compare loss characteristics. The measured insertion of micro strip lines on a LCP
substrate (25µm) and a polyimide substrate (25µm) is 0.11dB/mm and 0.18dB/mm,respectively. These results show that LCP has excellent and stable dielectric properties at high frequencies and the data suggests that this material can be used for applications extending through millimeter wave frequencies. LCP’s inherent properties such as multi-layer capabilities,excellent electrical properties,flexibility,and near hermetic nature suit it to a wide range of applications such as passive devices,packages,and RF cables. Finally,we demonstrate the development of a ban pass filter on LCP flex to achieve an
insertion loss less than 1 dB at 6 GHz in the pass band. The microwave characteristics of LCP have provided the feasibility of this material for low cost and high performance substrates for microwave and millimeter wave applications.

The data from the IPC Alternate Finishes Task Group Report “Time,Temperature and Humidity Stress for Final Finish Board Solderability” has been analyzed in a greater depth than in the actual report or a subsequent paper. Thermodynamically-based equations have been developed that are a better fit for the data than the intuitive ordering of the data in the report. Equations for the solderability results for the immersion silver,immersion tin,reflowed tin/lead,OSP and ENIG and the bare copper finishes studied in the IPC report are included here.