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Today a large variety of printed circuit board (PCB) base materials exists on the market and new ones are added frequently. The base material suppliers, having good original equipment manufacturer (OEM) marketing, usually present the materials in an early development stage to the end customers. The customers, on the other hand, expect from their PCB suppliers that the materials are fully characterized and that qualification samples are available immediately. In many cases, the process recommendations given to the PCB manufacturers are very generic (“like FR4”), insufficient, or not practicable (“8 hours baking time”). However, optimized processing ensures the reliability of the finished PCBs, starting from general leadfree compatibility to CAF testing. This demonstrates the importance of thoroughly verified process parameters and of very specific process recommendations to minimize the number of costly and time‐consuming iterations, and to be able to meet the goal of submitting qualification samples and functional PCBs in minimum time. The purpose of this paper is to show the minimum required PCB processing recommendations, and why these have to be fixed by the material supplier before commercialization of a new base material.

The paper examines the base material suppliers' situation, customer expectations and reality and the PCB manufacturers' expectations.

The paper gives the reasons and consequences of early base material marketing.

The paper analyses today's PCB base materials market and shows the reasons and consequences of early base material marketing. Also, the minimum requirements by PCB fabricators concerning processing recommendations are given.

The design and technological requirements of base materials for PCB production are considered. The problems of catalytically active base materials development and production are also discussed. Examples of the realisation of the problem under consideration are given.

Currently, the most widely used Printed Circuit Board (PCB) base material is the glass reinforced epoxy known as FR‐4. To improve the electrical or the thermomechanical performance of PCBs, there are two possibilities from a material standpoint: a modification or change of the resin system and a change of the reinforcement. Currently, there are a number of resins used for high performance PCB base materials. These resin systems offer higher Tgs and lower z‐axis‐expansions for improved through hole reliability. Non‐halogenated epoxy resin systems are offered for the production of green PCBs. In addition to new resins, new reinforcements are available for use in PCBs. Which can improve the electrical parameters of the base material and the x and y axis‐ thermal expansion also changes with the use of those reinforcements. This paper compares the thermomechanical and electrical parameters of some new high performance and green base materials with the glass reinforced epoxy materials commonly used in both high layer count boards and microvia applications.

Aims to explain the main requirements for printed circuit boards (PCBs) and to determine the survival rate of boards in lead‐free assembly.

The first two main requirements are the survival of 5‐6 cycles lead free reflow with peak temperatures of up to 260°C and an identical or even better board reliability of such boards compared to todays eutectic soldered ones. In a first series of tests the influence of base materials, reflow temperature gradient and peak temperature on PCB survival rate are investigated. Thermo‐mechanical data of different epoxy‐based materials are compared to survival rate investigations using repeated reflow tests. The impact of PCB manufacturing and design on the lead free performance is discussed. A second series of investigations is air‐to‐air life cycle tests of daisy chain boards out of different epoxy‐based materials with varying preconditioning were done.

The tests showed that dicy cured epoxy base materials are not able to withstand the thermal stress of the mentioned soldering steps. Board design and the heating gradient in reflow also influence the assembly performance. Thermal cycling tests (air‐to‐air), showed clearly the effect of reflow temperature and number of reflow cycles on through‐hole reliability. There was no significant impact of z‐axis‐expansion on the through‐hole failure rate in air‐to‐air cycling.

Provides further information on the lead‐free assembly of PCBs.

In order to meet international standards, PCB base materials have to be flame‐retardant according to the UL 94V specification. Up to now this has been achieved with FR‐4 materials by using brominated aromatic components. Unfortunately, in the case of fire or smouldering, these materials evolve highly corrosive and, under unfavourable conditions, even highly toxic decomposition products. In the search for flame retardancy without the use of bromine, the effect of different structural elements on the burning behaviour of cured resins has been investigated. As a result of these investigations an epoxy resin was developed which contains tailor‐made N‐ and P‐ containing constituents that form flame‐retardant structures during processing and curing of the material. The new material meets all requirements for printed circuit boards and can be processed without any need to modify established technologies. Analytical and ecotoxicological investigations of the combustion products of the new material show that they are comparable with those of wood from the beech tree. The project has already produced first samples of a PCB assembly that successfully passed all functional tests.

There is increasing customer demand for materials with low dissipation factors for reduced loss along the traces and low dielectric constants for higher signal propagation speeds. High performance epoxies such as Nelco's N4000‐13, Isola's FR408 and General Electric's GETEK (similar to Matsushita's MEGTRON) have become essential for boards operating in the higher frequency range. For applications at the highest frequencies material choices are very limited. These materials, tailored for high frequency use, have disadvantages – either with their thermomechanical properties or with their processability. Recently, a number of new “high frequency” or “low loss” materials have been introduced by different suppliers. In an overall relatively small but growing market, these materials have to demonstrate their advantages – from an electrical, thermomechanical, processing, fabrication quality and/or cost standpoint when compared to the established materials. This paper compares the thermomechanical performance and fabrication quality of new “high frequency”/“low loss” base materials.

In this paper, analytical modelling of heat distribution along the thickness of different printed circuit board (PCB) substrates is presented according to the 1 D heat transient conduction problem. This paper aims to reveal differences between the substrates and the geometry configurations and elaborate on further application of explicit modelling.

Different substrates were considered: classic FR4 and polyimide, ceramics (BeO, Al₂O₃) and novel biodegradables (polylactic-acid [PLA] and cellulose acetate [CA]). The board thicknesses were given in 0.25 mm steps. Results are calculated for heat transfer coefficients of convection and vapour phase (condensation) soldering. Even heat transfer is assumed on both PCB sides.

It was found that temperature distributions along PCB thicknesses are mostly negligible from solder joint formation aspects, and most of the materials can be used in explicit reflow profile modelling. However PLA shows significant temperature differences, pointing to possible modelling imprecisions. It was also shown, that while the difference between midplane and surface temperatures mainly depend on thermal diffusivity, the time to reach solder alloy melting point on the surface depends on volumetric heat capacity.

Results validate the applicability of explicit heat transfer modelling of PCBs during reflow for different heat transfer methods. The results can be incorporated into more complex simulations and profile predicting algorithms for industrial ovens controlled in the wake of Industry 4.0 directives for better temperature control and ultimately higher soldering quality.

The driving forces behind recent significant improvements in organic packages for microelectronic applications are electrical performance, product weight, size and manufacturing cost. A very careful selection of optimum manufacturing processes, equipment and materials, and stringent control of critical manufacturing operations are prerequisites for success in this emerging market place. Major technical and business related challenges to a printed circuit board manufacturer who plans to enter this market are discussed.

The new military specification for PCB base material was published on February 11th, 1987. This ‘G’ version is not merely an amendment of the ‘F’ version, but basically a new specification with far reaching consequences for both the base material manufacturers and the printed circuit board manufacturers. In this paper the major changes and also the latest introductions are discussed.

The purposes of this paper are to study the characterization of drill bit breakage in printed circuit board (PCB) drilling process based on high-speed video analysis and to provide an important reference for micro drill bit breakage prediction.

Based on PCB drilling experiment, the high-speed camera was used to observe the micro drill breakage process and the chip removal process. The variation of chip in the drilling process was studied and one of the key reasons for the drill bit breakage was analysed. Finally, the swing angles’ feature during the breakage process of the micro drill was analysed and researched with the image processing tools of MATLAB.

The micro drill was prone to breakage mainly because of the blocked chips. The breakage process of the micro drill can be divided into the stage of stable chips evacuation, the stage of blocked chips and the stage of drill bit breakage. The radians of swing angles were basically in the range of ±0.01 when the drilling possess is normal. But when the radians of swing angles considerably exceeded the range of ±0.01, the micro drill bit may be fractured.

This paper presented the method to study the characterization of drill bit breakage in the PCB drilling process by using high-speed video analysis technology. Meanwhile, an effective suggestion about monitoring the radians of swing angles to predict the breakage of micro drill bit was also provided.