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.

Printing technologies provide a simple solution to build electronic circuits on low cost flexible substrates. Materials will play important role for developing advanced printable technology. Advanced printing is relatively new technology and need more characterization and optimization for practical applications. In the present paper,we examine the use of different materials in the area
of printing technology. A variety of printable nanomaterials for electronic packaging have been developed. This includes nano capacitors and resistors as embedded passives,nano laser materials,optical materials,etc. Materials can provide high
capacitance densities,ranging from 5nF/inch2 to 25 nF/inch2,depending on composition,particle size and film thickness. The
electrical properties of capacitors fabricated from BaTiO3-epoxy nanocomposites showed a stable dielectric constant and low loss over a frequency range from 1MHz to 1000MHz. A variety of printable discrete resistors with different sheet resistances,ranging from ohm to Mohm,processed on large panels (19.5 inches x 24 inches) have been fabricated. Low resistivity materials,with volume resistivity in the range of 10-4 ohm-cm to 10-6 ohm-cm depending on composition,particle size,and loading can be used as conductive joints for high frequency and high density interconnect applications. Thermosetting polymers modified with ceramics or organics can produce low k and lower loss dielectrics. Reliability of the materials was ascertained by IR-reflow,thermal cycling,pressure cooker test (PCT),and solder shock. Change in capacitance after 3X IRreflow and after 1000 cycles of deep thermal cycling (DTC) between -55oC and 125oC was within 5%. Most of the materials in the test vehicle were stable after IR-reflow,PCT,and solder shock.

As the electronics industry moves toward smaller form and fit factors,advanced packaging technologies are needed to achieve these challenging design requirements. Current design problems are not driven by circuit design capabilities but by an inability to reliably package these circuits within the space constraints. Innovative packaging techniques are required in order to meet the increasing size,weight,power,and reliability requirements of this industry without sacrificing electrical,mechanical,or thermal performance.
Emerging technologies such as those imbedding components within organic substrates have proven capable of meeting and
exceeding these design objectives. Imbedded Component/Die Technology (IC/DT®) addresses these design challenges through imbedding both actives and passives into cavities within a multi-layer printed circuit board (PCB) to decrease the surface area required to implement the circuit design and increase the robustness of the overall assembly. A passive thermal management approach is implemented with an integrated thermal core imbedded within the multi-layer PCB to which high power components are mounted directly.
This paper discusses the design methodology,packaging processes,and technology demonstrations of prototypes packaged
using this technology. The various prototypes designed and manufactured using this technology will be presented.

Traditional SMT assembly is a two dimensional process. Each component is placed on the same horizontal plane in different
X and Y locations. In Package on Package (PoP) assembly,components are placed on successively higher layers. Since
components are stacked on top of each other,traditional solder paste printing cannot be used. The typical SMT method to
print solder paste can only be used to print paste on a single horizontal plane. For PoP,the components that are placed on top
of existing components need to have flux or special dipping solder paste applied at the time of assembly. This paper will explore the challenges and solutions of PoP assembly for the SMT assembly system.

Consideration and selection of dip transfer flux and solder paste for PoP assembly are described,based on process consideration. The crucial properties vital for successful dip transfer include homogeneity,open time on flux/paste bed,volume and consistency of dip transferred material,open time after dip transfer before reflow,and solder joint formation. For each property,one or more practical test methods recommended are described. Overall,this work should provide the assembly house an easy way to select a flux or solder paste adequate for dip transfer PoP assembly applications.

- 3D Manufacturing solutions: Flexible integration
- 3D/SiP Cost of Ownership
- Die vs. Package Stack Analysis
- Smartphone
- Package evolution
- Handheld Processor Roadmap
- PoP
- TMV
- Future Directions for 3D packaging

Examples of various types of parts machined through PCM processes are described.

Examples of various parts machined by PCM processes are featured.

Photochemical machining (PCM) is an excellent method for manufacturing both simple and complex parts in a wide range of
engineering materials. In the harsh economic climate facing manufacturing industry today,it is important to utilise costeffective
processes to produce high-quality parts rapidly for just-in-time delivery. This paper discusses the best methodologies to utilise PCM to its full extent as an extremely versatile process within the electronics,electrical and mechanical engineering disciplines.