Although the vast majority of electronic equipment has made the transition to lead-free without significant issue,some market segments still utilize tin-lead solder. The European Union’s RoHS legislation currently exempts server,storage array systems and network infrastructure equipment from the requirement to use lead-free solder (exemption 7b). The reliability of network infrastructure equipment in Finance,Health Care and National Security applications is critical to the health and safety of consumers,countries and the global community and the long term reliability of these end products using lead-free solder is not completely understood.
In addition to Government regulations,the conversion of high end server and network applications to lead free is also being hastened by the limited availability of tin-lead components. Although the exact conversion date is unclear,the requirement to ultimately convert these complex products to lead-free is absolutely clear.
The successful transition of low end and mid-range server applications to lead-free has come largely through wave solder process optimization and the use of alternate lead-free alloys for mini-pot rework.
Copper dissolution has become an industry buzzword and numerous studies have concluded that the current industry standard procedure of using the mini-pot for PTH Rework will not provide the capability to rework extremely large,high thermal mass network/server PCB’s even when SAC305 is replaced with alternate lead-free alloys such as SN0.7Cu0.05Ni (SN100C) with lower copper dissolution properties. These new rework challenges are reviewed in detail along with potential alternatives to mini-pot rework for these high end applications.

Automated Optical Rework (AOR) is a new method of reworking shorts by using a fully automated fine laser beam to ablate
any excess copper in fine-line PCB patterns. This includes shorts,protrusions,copper splashes,minimum space violations,under etched conductors,excess features and more,without damaging the panel’s substrate.
In the traditional PCB production process,following automated optical inspection of a panel,the operator of the verification system manually reworks any excess copper using a knife. Manual rework can damage the adjacent conductor,penetrate the
laminate,create cosmetic defects in outer layers and more. In fine-line production (sub 60µm),quality manual rework is not
possible,even by highly skilled operators. This includes,for example,the most advanced smart phone designs with line and space of sub 50µm and prepreg lamination thickness of 40µm and below. In addition,many PCB shops’ customers prohibit manual rework of PCBs. The technological solution for automated rework that has been developed offers: • Support for fine-line products (down to L/S resolution of 30µm).
• Fast rework - typically 60 reworks per hour (including handling) for typical high-end HDI production
• High quality – minimum damage to laminate; typical penetration of 15µm or less
• Accuracy - deviation from reference of less than 10% • Repeatability - all reworks are of the same high quality • An automated process – no human intervention AOR introduces a closed-loop technology of iterative processes that consist of three parts: • Image acquisition - captures white-light and UV images. • Image processing - analyzes and compares the images with the CAM reference data and defines the accurate ablation contour and parameters. • Laser ablation - based on the processed data,shorts are reworked using laser ablation The quality results of AOR are now well-proven for even the most complex PCB designs. The latest technology
breakthrough in higher speed with no compromise on rework integrity has cleared the way for more widespread and mainstream use of this technology in the manufacture of today’s demanding PCB applications. The advantages of AOR provide new opportunities for fabricators to move much closer to achieving zero scrap production,while continuing to push the boundaries of electronics innovation. This technical paper will describe Automated Optical Rework technology and its advantages for advanced printed circuit
board production including examples of actual before and after results.

As more components are becoming lead free and not available in the tin lead alloy,there is an industry wide interest when it comes to the reballing and the subsequent effects it has on the strength of those components. This is particularly true for legacy parts needed for military applications some of which use tin lead solder. There is cause for concern due to the potential mixing of alloys and the differences in reflow temperatures of the two different alloys. Additionally,there are unknown characteristics regarding the intermetallics that are formed due to the potential of mixed alloys. This research paper will focus on the effect of various parameters that are used to reball a BGA and their effect on the overall shear strength. Factors that will be looked at include the type of BGA (SAC305 or 63Sn/37Pb),the alloy used to reball (SAC405 or 63Sn/37Pb),the type of flux used (Water Soluble or No Clean),and the environment in which reballing takes place (Nitrogen or Ambient). Being most relevant to industry demands,the focus will be on the effects of reworking a BGA with a base alloy of SAC305 and reballing it with 63Sn/37Pb. After the reballing of the component is complete,samples will be both shear tested and cross sectioned as a method of evaluation. The shear tests will determine the strength of the newly formed solder balls while the cross sections allow for the observation of the solder ball and the bonding characteristics of the new solder alloy to the pad on the BGA. The cross sections will also allow for observation of any defects or abnormalities through the reballing process. When the experimentation is completed,the goal is to determine the optimal factors that should be used in the creation of a robust process for BGA reballing.

•Jet printing introduction
•Industry challenges
•Jet printing low temperature paste
–Collaboration Alpha-MYDATA
–Rheology
–Results
•Low temperature paste offers a production solution for advanced applications
•Jet printing furthers these opportunities

Low Temperature Conversion
•Substantial cost savings over regular processes
•Savings can outweigh paste cost differences
•Can be mechanically stronger if done right
•Involves more than just changing pastes
•Beware of excessive flux residue
•Pick on plastic components / flex circuits
•Avoid high peak temperature

Low temp solders are a viable solution and their
performance can be enhance thought final finish
selection.
Initial data suggest that an organic metal final finish
in combination with a low temperature solderpaste
can out perform standard paste and OSP in the tests
performed.

New Low Temp. Alloys were developed,through elemental additions,to improve mechanical strength,fatigue life and drop shock resistance.
•Effect of these elemental additions on the new alloys was evaluated using:
–Alloy strength,
–Ductility,
–Thermal conductivity,
–Copper dissolution,
–Creep properties,and
–Bulk and interfacial microstructure stability

Microsystems Enabled PV:
•Technology benefits
•Process flow/assembly examples
•Cost analysis
•From R&D to commercialization
•3DIC/hybrid assembly and new functionality

For the past few years there has been a shift in the Lighting Industry that has carried over to the surface mount technology assembly line. What is this shift you may ask? Well it is the LED revolution. This revolution or change in lighting has some very promising results already in practice and many more companies looking to implement the LED technology into their product portfolio’s. With a number of companies looking to expand their portfolio to include LED fixtures there has been an increase in the number of companies that have started their own SMT lines,as well as a significant number of contract
manufacturers to meet this new industries demands. With this surge in the new style of lighting the manufacturers need the automated pick and place process to achieve the throughputs that are being forecasted; there has been a sudden increase of companies that have faced issues around the pick and place process with less than desirable results. The automated pick and place systems have been used for high-speed,highly accurate placement of a wide range of electronic components. A major factor in the automated pick and place manufacturing for surface mount devices (SMDs) is that most of the components previously being placed have been in use since the1980s. These process parameters and speeds specified have been focused on a solid or hard epoxy molded,flat topside packages,like capacitors,resistors and integrated circuits. Over the multitude of years since the inception of the automated pick and place system,the parameters used to control the equipment have been refined. Now that there is a new product in the industry; it may require some adjustments,Especially when LEDs with a glass or soft silicone molded dome are introduced. This presentation will discuss some issues in the pick and place process for LEDs and presents a method to troubleshoot and resolve these issues.

This paper is the first of two papers discussing the Celestica/Honeywell Lower Melt Alloy program. The program explores the manufacturability and reliability for Pb-freethree Bi-containing alloys in comparison with conventional SAC305 and SnPb assemblies. The first alloy included in the study is a Sn-based alloy with 3.4%Ag and 4.8%Bi which showed promising results in the National Center for Manufacturing Sciences (NCMS) and German Joint (GJP) projects. The other two alloy variations have reduced Ag content,with and without Cu.
BGA and leaded components were assembled on medium complexity test vehicles using these alloys,as well as SAC305 and SnPb as base line alloys for comparison. Test vehicles were manufactured using two board materials,170°C glass transition temperature (Tg) and 150°C Tg,with three surface finishes: ENIG,ENEPIG,and OSP. The ATC testing was done at -55°C to 125°C with 30 minute dwells and 10C/min ramps. Vibration at two G-Force test conditions with resistance monitoring was performed. In this paper,the detailed microstructure examination before testing and after 1500 cycles of -55°C to 125°C,together with failure analysis,is described. These results allow preliminary recommendations of proper combinations of the solder alloys,board materials,and surface finishes for high reliability applications.