In this study,the reliabilities of low Ag SAC alloys doped with Mn or Ce (SACM or SACC) were evaluated under JEDEC drop,dynamic bending,thermal cycling,and cyclic bending test conditions against eutectic SnPb,SAC105,and SAC305 alloys. The Mn or Ce doped low cost SAC105 alloys achieved a higher drop test and dynamic bending test reliability than SAC105 and SAC305,and exceeded SnPb for some test conditions. More significantly,being a slightly doped SAC105,both SACM and SACC matched SAC305 in thermal cycling performance. In other words,the low cost SACM and SACC achieved a better drop test performance than the low Ag SAC alloys plus the desired thermal cycling reliability of high Ag
SAC alloys. The mechanism for high drop performance and high thermal cycling reliability can be attributed to a stabilized
microstructure,with uniform distribution of fine IMC paricles,presumably through the inclusion of Mn or Ce in the IMC. The cyclic bending results showed SAC305 being the best,and all lead-free alloys are equal or superior to SnPb. The reliability test results also showed that NiAu is a preferred surface finish for BGA packages over OSP.

Thermal cycling tests were conducted using two different ceramic ball grid array (CBGA) test vehicles having balls comprised of nine different Pb free solder alloys. The experiment was designed as a screening experiment to obtain data comparing thermal fatigue reliability of the various solder ball alloys. The test matrix was dominated by commercial SnAgCu (SAC) alloys but also included other high,low,and no-Ag alloys. The surface mount assembly was done with SAC305 (Sn3Ag0.5Cu) solder paste. The thermal cycling data,Weibull analyses,and metallographic failure analysis indicate that the best thermal fatigue performance was obtained with higher Ag alloys.

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Current carrying capacity in printed board design is technology dependent and an element of printed circuit board thermal
management. Conductor temperature rise as a function of current is dependent on the number of copper plane layers in the board,how the board is mounted,the ambient environment (air or vacuum),board thickness,board material,conductor thickness,and conductor width. How does one go about creating a single standard for something that is so variable dependent?
IPC2152,Standard for Determining Current-Carrying Capacity in Printed Board Design,begins with a baseline configuration that provides a conservative method for sizing conductors for carrying current in printed circuits. New charts included in IPC-2152 are based on tests conducted on traces in boards with no copper planes,suspended in still air as well as in vacuum. The baseline represents a defined board thickness,board material,conductor width and thickness,as well as variations with respect to those variables.
IPC-2152 is a technology enabler. Through the use of computer modeling and information within IPC-2152 and the Appendix,current carrying capacity design guidelines can be optimized for any variation in printed circuit technology. Until the publication of IPC-2152 this was not possible with the available public information.

• The standard covers marking and labellingof both tin-lead and lead-free components,boards and solders used in 2ndlevel assembly.
• Other areas covered include board base material type and surface finish,conformal coating and component temperature rating.
• A major update of IPC JEDECJ-STD-609A has been the addition of the e8 material code which helps to describe and clarify materials codes for e1 and e2 together with e8 in terms of silver content.
–e1–SnAgCu alloys with silver content greater than 1.5% and no other intentionally added elements e.g. Sn3Ag0.5Cu
–e2-tin (Sn) alloys with no bismuth (Bi) nor zinc (Zn),excluding tin-silver-copper (SnAgCu) alloys described in e1 and e8 e.g. Sn3.5Ag
–e8-SnAgCu alloys with silver content less than or equal to 1.5%,with or without intentionally added alloying elements with no bismuth(Bi) or zinc (Zn) e.g. Sn1Ag0.5Cu

• The Information Process
• Knowing the jargon (terms & definitions)
• Defining the requirements
• Expansion of Documentation standards
• Document Grade and Completeness
• Relationship of CAD/CAM Data Standards
• Feed back mechanisms (archiving)
• Future activity

This paper will focus on understanding the dielectric constant (dk) of high frequency laminate materials. The dissipation factor (df) and other electrical properties will be discussed as well,however in less detail. There are many different methods that can be used to determine these properties and each of them have their own capabilities and potential shortcomings. And if a very accurate dk value is found,by the nature of the high frequency circuit design,it may experience a slightly different value. This paper is formatted in three sections. The first is discussion on the effects of circuit design,as it relates to variation of dk. Next is test methods used for testing the high frequency laminate materials. And third will be discussion on the substrate construction and how that can affect dk values. Two of the most common test methods will be discussed,as well as their capabilities and results on varying types of materials. Also some variation of these test methods will be shown in order to have enhanced testing capabilities. The test methods discussed will be from IPC-TM-650 and they are the clamped stripline resonator and the full sheet resonator (FSR) test. Microstrip transmission line testing will be discussed as well.

In this paper,ITEQ demonstrates outstanding performance of new halogen-free and low loss laminates,IT-258GA,IT-168G,and IT-150D,for the coming halogen free generation,and higher frequency applications. Especially,IT-258GA exhibits excellent thermal reliability,and very suitable for LCD,NB,consumer electronics. IT-168G is the pioneer product with halogen-free and low Dk/Df values.

Printed circuit board laminate datasheets provide permittivity (dielectric constant,Dk) and loss tangent (dissipation factor,Df) values that are used for specification and board design. But past studies have shown that these properties vary with changes in the moisture content of the PCB laminate material and a major predicament can arise when material substitutions are made using laminate datasheets as a guide,especially when the data is derived using dissimilar test conditions or methods. For example,initial impedance calculations on the basis of datasheet values may be acceptable,but actual board performance may be significantly different and may result in poorly functioning and unreliable boards.
This experimental study establishes whether the preconditioning steps outlined in the IPC-TM-650 2.5.5.9 (Permittivity and Loss Tangent,Parallel Plate,1MHz to 1.5 GHz) test standard account for varying moisture contents in PCB laminate test coupons. The moisture content in a PCB material may vary because of material constituents,board design or handling,processing,shipping and end use conditions. Additionally,this study also sheds light on the dependence of dielectric values on moisture content and type of flame retardant used. Commercially available PCB materials sourced from two manufacturers were tested in this study. Materials were classified on the basis of flame retardant type (halogenated or halogen-free) and glass transition temperature. The extent of variation in the dielectric properties is discussed as a function of material constituents and moisture content. The types of materials that are most affected and reasons behind the variation are also reported.

Demands for higher data rates and capacity have continued to drive RF and Microwave electronics continue toward higher
frequency and higher power requirements. These power and frequency demands have increased the heat burden on power
amplifiers and related electronics while competing requirements have pushed to reduce device size and weight while exposing electronics to greater environmental conditions. The resulting combination has been a decrease in overall efficiency resulting in higher operating temperatures and a resulting decline in reliability. Most RF system engineers highlight the "Arrhenius Equation," in which a 10°C increase in operating temperature doubles the failure rate for a typically component. In other words,the ability to get heat away from components,reduce or eliminate hot-spots,reduce overall device operating temperature will increase product life. Innovations focused on increasing thermal conductivity and temperature stability of the dielectric while maintaining low loss are being introduced in the industry. A benefit to these advances can result in greater phase stability,which is critical to impedance network transformers utilized for matching networks of power
amplifiers. For power amplifiers,the shift in dielectric properties with temperature increases reflections and directly reduces
efficiency. For antenna designs,a significant shift in resonance frequency and bandwidth roll off at specific frequencies,results in lower gain performance. The resulting combination of new materials with better heat transfer and better thermal stability of the dielectric results in devices that operate more efficiently and more reliably over time. Applications and test data have shown the benefit of increased board thermal conductivity on reducing the maximum case temperature of the RF power amplifier FET transistors,as demonstrated by the hot spot thermal images of experimental boards with different thermal conductivity properties. TDR (time-domain reflectometer) tests have also shown that the temperature stability of dielectric constant in RF/Microwave laminates provides greater stability of electrical phase or electrical length in high frequency circuit elements that phase shifts greatly affect the performance,such as the impedance matching networks in power amplifiers.