Solid Solder Deposit (SSD) technology was developed in the early and mid-1990's to improve first pass yields in the manufacture of electronic devices. As the trend towards finer pitch surface mount devices accelerated an alternative to conventional solder paste printing at assembly was desirable. Over 60% of defects in the assembly process have been attributed to the paste printing operation. These defects include solder shorts,insufficient solder/opens,and component skew. With the implementation of higher density devices,i.e. components with pad pitch spacing of .020" (Figure 1) and below,assembly yields declined dramatically. Yields were further exacerbated by the lack of planarity of the hot air solder leveling surface finish. Smaller pad geometries,as well as limitations in the solder leveling process and equipment,made it difficult to maintain a planar finish on double sided surface mount devices,particularly with the most prevalent vertical systems. A higher incidence of solder tails and shorts was more pronounced on fine pitch products. Further hot air leveling could cause thermal degradation,which may result in warp,delamination or solder mask related failures.

In many areas conductive polymers have already gained full acceptance as a reliable and qualitatively outstanding metallization process and as a true competitor for electroless Cu. In the paper presented the entire process sequence is explained,with the process not being a series of individual steps with individual functions,but a rather logical and most elegant sequence of interrelating chemical systems. Process details down to a molecular level are being revealed,information necessary to grasp the full meaning of each physical or chemical reaction occurring. Various process options are being discussed with a particular focus on the selection of monomers,acids in the polymerization step and buffer systems for the preceding MnO2 formation,knowledge which formed the basis for a recent process reengineering. Finally a series of HDI production results will be shown,demonstrating why conductive polymers are already the most successful PTH alternative to electroless Copper.

Processing thin core capacitor materials can be challenging,particularly those with non-reinforced dielectric less than 0.001” thick. Several processing steps require special attention to ensure the material is not damaged during manufacturing. Material storage and loading systems,conveyor systems and lamination systems must be capable of handling thin core material. Equipment modifications or special fixtures may be required in order to reduce the risk of jam-ups or fractured material. Special attention to cleanliness and the documentation of careful handling practices are also important. This paper will review some of the lessons we have learned about processing thin core capacitor materials from our participation in the NIST Advanced Embedded Passives Technology consortium.

A new versatile laser technology is available that is capable of working with both rigid and flexible boards using only one laser source. This system is based on a THG-UV laser (355 nm) and vector data software. This system can be used for drilling,cutting and structuring. Small and medium board manufacturers will be able to enter the HDI market with a minimum investment and a guaranty of high yields for each technology step. Various materials and combinations including glass fiber reinforced substrates can be drilled,cut and structured with the same equipment. This paper will introduce special applications in the area of micro via formation (minimum diameter of 30?m at 250
holes per second),laser direct structuring (minimum line widths of 0.8mil at 13.8 inches per second) and routing (compounds of various materials ) and will discuss the technological benefits.

Because of environmental concerns,elimination of lead from electronic components has been recently encouraged,and as a result,lead-free solders are frequently adopted for solder mounting. The OSP and HASL treatments have been primarily used for the majority of final surface treatments for PWB’s used for electronic components,while conventional electroless Ni/Au plating process has been used for the remainder. Lead-free solder mounting can lead to poor solderability in the case of some OSP-treated PWBs. The problems associated with HASL for the latest generation PWBs and packages is already well documented. Under the present conditions in which manufacturers are switching from conventional solders to lead-free solders and are beginning mass-production,this problem is being highlighted. Consequently,it is urgently required to establish a treatment method that can replace OSP treatment. This paper compares the solderability of immersion Ag,immersion Sn,and immersion Au plating that is treated directly on copper,and electroless Ni-P/Au plating,all of which are now attracting industry wide attentions as alternative surface treatments for PWB’s. The paper makes recommendations regarding the treatment method that supports future lead-free solder mounting.

The market for optical communication equipment and components has grown significantly since the early 1980s with growth rates exceeding 50% annually in the late 1990s. Although demand has dropped significantly since 2000,the underlying drivers for demand are still operating. This paper discusses the drivers for optoelectronic devices and optical PWBs,the major differences between IC packaging and optoelectronic device packaging,the emerging evolution of optical printed circuit board,and some of the opportunities for assembly and materials suppliers in these areas.

An optical interconnection technology for multi-layer printed circuit boards is presented. The application of this technology enables onboard data rates of several Gbps whereas at the same time a significant improvement on the electromagnetic compatibility (EMC) can be achieved. After an introduction,the most important properties of electrical interconnects are compared with those of optical interconnects. Moreover,requirements are derived which are essential to be met for an industrial use of optical interconnection technology on the printed circuit board level. The most important one of these requirements is to ensure compatibility with the existing design,manufacturing,and assembly processes. In the second part the current state of the art of this new technology,which takes into account the different demands and requirements,is presented. Technologies for the manufacturing of optical layers,their integration into the printed circuit board,as well as coupling concepts enabling furthermore the pick & place process are presented and discussed. As an efficient employment of this new technology requires also an enhanced and efficient design process,the necessary extensions are introduced. This includes an overview on modeling and simulation techniques for the active and passive components whereas again compatibility with the existing printed circuit board design tools is essential.

The rapid developments of IT equipment are placing increased demands on printed wiring boards (PWBs) in terms of high efficiency,high-density and lightweight. Industry experience has proven that glass fiber base materials are essential for highly reliable PWBs,in particular to obtain such characteristics as heat resistance,dimensional stability,and mechanical strength and insulation reliability. There can be some difficulties in the processing of traditional PWB laminating in terms of accuracy and cost performance applications are focused on fine glass fiber fabric developments. Resin coated copper foil (RCC) is used widely as layer material for build-up (sequential) processing technology as a solution to these accuracy issues. However,in RCCs increasing use,much higher reliability such as no warp and crack and correspondingly improved dimensional stability and high cost performance are being demanded. We are investigating new glass base materials to overcome these deficiencies in both systems by developing improved spinning and binder technology in a novel,non-woven glass fiber fabric (FF sheet). This novel base material for microvias is able to bring high reliability,good processing and also high productivity as an improved
RCC alternative.

The next generation of surface finish coatings to replace HASL are now being installed by various PWB manufacturers and have been implemented by many OEMs. Coating thickness requirements are part of the OEMs’ specification given to the board manufacturer. Clearly from previous and existing final finish coating performances,thickness has shown to have a major impact on the performance of the surface finish during soldering. OEMs have traditionally specified wide thickness specifications,to meet production variations by PWB producers. This paper investigates the current methodologies / alternatives used to determine accurately and consistently the thickness of these new immersion silver & tin coatings,and how this variation may impact solderability performance under various pre-conditioned states.

Dry film photoresist to produce highly integrated and advanced PWBs has been developed to meet more demanding
fine line requirements.
Advantages for volume production of fine features below 50?m with high yield are now available with newly
developed dry film photoresist that is designed to have specific features. In order to develop such a highly reliable
dry film photoresist,Quality Function Deployment (QFD) helped significantly to well interpret 'Voice-Of-the-
Customer' (VOC) into specific requirement of dry film photoresist performance and how it can be achieved by
formulation design. The developed dry film photoresist resulted in L/S resolution and isolated adhesion better than
1:1 aspect ratio to thickness,with very wide exposure range,and with wide developing latitude.