Design for test rules (DFT) for in circuit test (ICT) test pads are well known and have served the industry well for nearly two
decades. However,increasing PCB densities continually put pressure on board designers to eliminate ICT testpads.
Furthermore,recent technical advances in operational board speeds are leading some designers to believe that ICT test pads
cannot be added in the high-speed sectors of boards soon to be designed. Since the effectiveness of ICT is directly related to
test pad access,some have questioned the long-term viability of ICT in this high density/high speed PCB environment.
Parker has introduced a new ICT probe technique in 2004 to address these issues.1 We’ve been calling them “bead probes”.
Parker shows that this new technique will not degrade the high-speed circuit performance of tomorrow’s gigabit logic boards.
He also presents test results showing that this new technique can be used with typical PCB assembly processes and ICT
fixtures with similar electrical performance and reliability to current ICT probing techniques.
This paper will continue that discussion and further demonstrate how these non-traditional pads have little impact on layout
for test pad placement using results from a real PCB design process. It will discuss DFT guidelines for “bead probes” and
discuss possible barriers to creating beads in an outsourced manufacturing environment. Finally,now that ICT access to highspeed
sectors on PCBs will be available,a survey of viable ICT test techniques will be presented.

The design and evaluation of a wide bandwidth (3 dB attenuation bandwidth > 20 GHz),50 S,coaxial probe for the
electrical characterization of printed wiring board (PWB) transmission lines is described. The probe made thousands of
repeated contacts,using spring-loaded interconnects,without affecting probe performance. The probe contains an internal
mechanism for dissipating static charge on the signal line of the PWB transmission line and is long enough (approximately
10 cm) to act as a transfer standard for characteristic impedance testing per the time -domain reflectometry test method
described in IPC TM 2.5.5.7.

In today’s complex manufacturing test environments,it is becoming increasingly difficult to detect and diagnose structural
faults within highly complex multi-layer PCB designs that offer extremely limited physical test access.
The widespread use of array style packaging i.e. BGA,CSP and FCA have resulted in significant limitations in physical test
access,reducing the effectiveness of conventional test methods such as in-circuit test in favor of other complimentary test
strategies. This is further complicated by the EU directive (WEEE and RoSH) that legislates that companies must adopt a
lead-free soldering process by 2006,which will have a significant impact on the effectiveness of physical contact probing
methodologies i.e. in-circuit test and flying probe testers.
This paper explores the utilization of boundary-scan as an alternative complimentary low-cost,high-performance but more
importantly a non-contact,fixture -less test methodology. It also examines the significant benefits offered by importing legacy
boundary-scan tests directly,without the need for redeveloping tests for execution on to a contract manufacturers preferred
test platform.

Small form factor and high density of printed circuit boards (PCB) have been already realized by flip chip (FC) bonding
technology. However,the requirement for finer pitch PCB is still increasing with shrinkage of die and wiring. Therefore,
conventional FC bonding technology will not provide sufficient capability or productivity to meet future demands.
The authors have focused on flip chip bonding method utilizing ultrasonic vibration. Flip chip modules using flexible printed
circuit (FPC) are strongly required for such as mobile phone applications. For that purpose,we investigated to assemble
semiconductor devices with FPCs applying this method,particularly for large size die with multiple pads. In this report,we
evaluated relationship between bonding parameters and reliability using several kinds of copper clad laminate (CCL) with
different plating conditions. We show the correlation between formation of microscopic metallic bond and actual chip on flex
(COF) module performance. As a result,we succeeded in realizing 35 micrometers pad pitch COF modules.

The comparison of the thermal pattern and the deformation pattern both are obtained on the surface of Printed Circuit Board
(PCB) was done to understand how both patterns correspond to each other. In the present study,both the FEMLAB simulator
and Thermography were employed for the study.
A Holographic Pattern Measuring System (HPMS) and an Interferometry Imaging System (IMS) were used. The test results
showed that both thermal pattern and deformation pattern were different from each other. We found that we could not deduce
the thermal deformed pattern on a PCB from its thermal pattern.

This paper describes part of a research effort currently under way in the field of print defect detection. The techniques
described have proven to be robust and particularly well suited for detecting troublesome bridge and bridge-like features that
span the gap between pads.

After the world electronic circuit industry finally turned out from the unprecedented recession,the business management of
today’s printed circuit industry may possibly have a chance to take a comfortable breather for a while. However,looking into
the trends and drivers of the industry,many people are still endeavoring to look for the next step in business development as
the competition environment is changing so rapidly. Today,China’s electronics market catches much attention for the
business people both in China and around the world. Driven by relocation,restructuring and supply chain management and
changes in China’s electronics manufacturing market and printed circuit supply,there are more features of China printed
circuit industry today,both with market opportunities as the industry is developing and with challenges which have to be
watched and turned into business development opportunities. Behind the growth of the China printed circuit market,there is
much more to improve and to collaborate.

The world market is changing for the OEM,CEM,and electronic manufacturers. This changing market dictates that as a
global industry more focus is placed on reducing the time to market for “New Product Introduction”. The current process has
many redundant steps and requirements that greatly vary from one OEM or CEM to another. The transfer of the data and
information required to build the design are ineffective. Often the fabricators receive designs with erroneous or incomplete
information,resulting in even more delays in introducing the product to the marketplace. This is further compounded because
prototype PCBs are frequently built at one facility and then transferred to another manufacturer or split between manufactures
for production. The problems that are found at the prototype stage are not fixed before it is transferred to production,and the
new production facility must once again deal with the same issues as the prototype manufacturer.
As the intricacy of the NPI process and the complexity of design requirements increase,the need for software tools grows
dramatically. A fully integrated process from predesign analysis,where the designer is determining the initial characteristics
of the design,through to the final product reaching the customer is essential,given today’s environment. This paper describes
a process that builds value into each step of the NPI job flow and retains the information for use throughout the entire
process. Quality checks must be performed throughout the NPI process,and the design integrity must always be maintained
even when transferring the design from one manufacturer to another. With the global placement of designs for prototyping
and production,consistency in the design’s performance,regardless of where it is manufactured,and a historical record of the
design’s life cycle are necessary so that the product’s performance is never compromised or derogated.

It is effective to use the stack-via-holes method (via-on-via structure),which stacks micro via-holes (MVH),in the
development of higher density circuits on build-up printed wiring boards. When micro via-holes are repeatedly stacked,via
holes cause an open circuit due to the difference in the thermal expansion of the copper and the glass epoxy base material. In
order to verify the reliability of the stack-via-hole connection,we produced a range of test boards with differing numbers of
stack-via-hole layers,material types (FR-4,high-Tg FR-4,low thermal expansion material,etc.),and via hole diameters
(0.100 mm and 0.075 mm diameters). The boards were examined through DC current induced thermal cycling tests to
determine the reliability of the various samples.
In respect to the anti-migration properties,we also undertook research on pitches and base material types of micro via- holes.
As a result of the evaluation,it was verified that the MVH,then interstitial-via-hole (IVH),followed by the plated throughhole
(PTH) achieved the best connection reliability. As for base materials,it is recommended to use a high-Tg material with
low thermal expansion qualities. We believe that an MVH diameter of 0.100 mm is preferable to prevent any void attributed
from a high aspect ratio. No problem with the insulation reliability was found on any base material as long as the MVH pitch
is 0.35 mm or more (or 0.25 mm between the hole walls).

We report test results of bending characteristics of flexible printed circuit board,which contributes to the development of
higher density and more sophisticated function of mobile devices and electronic equipment. Our report shows that there is a
correlation between mechanical structure and the bending characteristics of flexible printed circuit boards,and that ultra thin
structure shows excellent performance in bending applications. We also find that elasticity modulus of adhesive plays a key
role in the bending characteristic of flexible printed circuit board. We have utilized the finite element method to evaluate the
strain for investigation of the bending fatigue mechanism. We will report on the study of a formula with which we can
estimate the flexural fatigue life. We also show the analysis result of generated stress when various constructions of flexible
printed circuit boards are bent.