• Summary of some new and existing technologies for printed electronics outside of traditional membrane switch manufacturing
• Discussion of requirements for understanding the technology of these applications in order to capitalize on them

Printed Electronics is generally defined as the patterning of electronic materials,in solution form,onto flexible substrates,omitting any use of the photolithography,etching,and plating steps commonly found within the Printed Circuit Board (PCB) industry. The origins of printed electronics go back to the 1960s,and close variants of several original applications and market segments remain active today. Through the 1980s and 1990s Printed Electronic applications based on Membrane Touch Switch and Electroluminescent lighting technologies became common,and the screen printed electronic materials used then have formed the building blocks for many of the current and emerging technologies and applications.
It has been only in recent years that the term Printed Electronics,with the inherent benefits of low cost manufacturing using additive processing,has captured the attention of a much wider audience. One consequence of this attention has been the rush to invest in new materials and patterning processes. While the results so far have generated some as yet unrealized market hype,there are many new and emerging applications that are just entering into production. But instead of requiring radical changes,many of these applications are using screen printed conductive materials that are fundamentally similar to those materials that have been used for over 30 years. We present here a review of both traditional and emerging applications
for Printed Electronics,with a focus on the printed functional materials. We also present several recent advances in the capabilities of conductive inks for various deposition methods.

– Define Printed Electronics
– Provide general market
information & Applications
– Provide performance
information on a wide variety
of thermoplastic films
– Provide processing
considerations for current
PE applications
– Provide incite into future
product developments

Printed Electronics is considered by many international technologists to be a platform for manufacturing innovation. Its rich portfolio of advanced multi-functional nano-designed materials,scalable ambient processes,and high volume manufacturing technologies lends itself to offer an opportunity for sustained manufacturing innovation. The success of introducing a new manufacturing technology is strongly dependent on the ability to achieve high final product yields at current or reduced cost. In the past,standards have been the critical vehicles to enable manufacturing success.
During the past few years the Printed Electronics Field has seen an increase in the number of companies attempting to scale-up their manufacturing processes for new product introduction. A key operations-related activity during this exercise is the establishment of a robust supply chain. Many of the printed electronics companies have negotiated unique quality conformance documents (i.e.,Certificates of Compliance) with each individual supply chain member. Also,these companies have made significant investments to develop internal standard operating procedures.
Historically,the adoption of standards has shown that it facilitates the growth of an emerging field and reduces the burden placed on individual companies to invest significant resources in the development of company specific compliance documentation. This paper provides an overview of the recently established IPC Printed Electronics Standards initiative.

There are few halogen free flame retardant laminates available and for those on the market currently,they are not considered mid loss and thermally stable. Theta circuit materials appear to be unique where they meet both these criteria along with other necessary requirements for good PCB fabrication and reliability. The difficulty is comparing materials to this unique material fairly. The appropriate comparisons were done here with materials that have a long proven record in the PCB industry and as a group these comparison materials have the attributes to verify thermal stability and mid loss performance. Through multiple lead-free solder reflows,288°C solder floats,eyebrow crack testing and other demanding high reliability tests not addressed in this paper,such as HATS,CAF,IST,liquid-to-liquid and moisture conditioning,it was found that this newly developed halogen free material is very
thermally stable. The electrical properties were found to be very good as well. The claim of a mid-loss material was verified from insertion loss testing compared to well-known low loss and high loss materials. Also,material dispersion of the dielectric constant was found to be very good and consistent over frequency which can enable a much more stable eye diagram for high speed digital applications.

Consumption electronic devices are becoming much smaller,lighter and multifunctional,and high CTI application has
already been not satisfied with double sided design and requested thinner & multilayer compatible. We developed a new
halogen free and high CTI RCC to meet these new requirements. Compared to traditional FR-4,it provides flexible
selection by combination with different material to meet fine line,lead free & halogen free application.

Tetrabromobisphenol-A (TBBPA) is the predominant flame retardant used in rigid FR-4 printed wiring boards (PWB). In
this application,the TBBPA is fully reacted into the epoxy resins that form the base material of the PWB. TBBPA’s
leadership position in the rigid printed wiring board market is due to several factors,which include reliable performance over
time. This paper will look at the benefits of TBBPA as a flame retardant in epoxy resin PWBs. It will also address the
current regulatory status of TBBPA. An update will be given on the regulatory and environmental status of TBBPA and
other industry assessments that compare TBBPA to alternative flame retardants for PB will be included.

We investigated the micro-void formation of solder joints after reliability tests such as preconditioning (precon) and thermal
cycle (TC) by varying the thickness of Palladium (Pd) in Electroless Nickel / Electroless Palladium / Immersion Gold
(ENEPIG) surface finish. We used lead-free solder of Sn-1.2Ag-0.5Cu-Ni (LF35). We found multiple micro-voids of less
than 10 ?m line up within or above the intermetallic compound (IMC) layer. The number of micro-voids increased with the
palladium (Pd) layer thickness. Our results revealed that the micro-void formation should be related to (Pd,Ni)Sn4 phase resulted from thick Pd layer. We propose that micro-voids may form due to either entrapping of volatile gas by (Pd,Ni)Sn4 or
creeping of (Pd,Ni)Sn4.

This paper will discuss a new approach to the final finishing for the PCB industry which is based on the use of an ultra-thin
fluoropolymer film as a protective coating to preserve solderability of the circuit board between manufacture and assembly.
The coating has been shown to extend the shelf life of the PCB by preventing oxidation and corrosion,and ensures excellent
solderability during assembly. The fluoropolymer coating is applied using a dry plasma deposition process,which eliminates
the use of harsh chemicals and waste streams associated with other surface finishes. The coating has been applied directly on
to copper,or can be used in conjunction with other surface finishes to act as a corrosion inhibitor when specific properties are
required,such as resistance to creep corrosion or tarnish.
Significant testing has been performed on the fluoropolymer coating to demonstrate its capability as a surface finish for the
PCB industry. The results of solderability testing,solder joint reliability testing and corrosion protection will be discussed.

As a surface finish,electroless nickel / electroless palladium / immersion gold (ENEPIG) has received increased attention
for both packaging/IC-substrate and PWB applications. With a lower gold thickness than conventional electroless nickel
/ immersion gold (ENIG) the ENEPIG finish offers the potential for higher reliability,better performance and reduced
cost.[1,2]
This paper shows the benefits by using a pure palladium Layer in the ENEPIG (Electroless Nickel,Electroless Palladium,
Immersion Gold) and ENEP (Electroless Nickel,Electroless Palladium) Surface Finishes in terms of physical properties
and in terms of gold wire bonding test results.