Epoxy surface mount

We should not think that heat is lost only from the copper side. The usual laminate (board material) used for SMT (surface mount technology) applications is epoxy-glass FR4, which is a fairly good conductor of heat. So some of the heat from the side on which the device is mounted does get across to the other side, where it contacts the air and helps reduce the thermal resistance. Therefore, just putting a copper plane on the other side also helps, but only by about 10 to 20%. Note that this opposite copper plane need not even be electrically the same point it could for example just be the usual ground plane. A much greater reduction of thermal resistance (by about 50 to 70%) can be produced if a cluster of small vias (thermal vias) are employed to conduct the heat from the component side to the opposite side of the PCB. 

Brominated epoxy resins are the reaction product of epichlorohydrin and brominated bisphenol A. They are primarily used in applications where ignition resistance is a requirement, such as printed-circuit boards and other products that need to be flame-retardant. Tetrabromobisphenol A is the largest flame retardant in terms of commercial use at present. It is used in an estimated 95 percent of all flame-retardant printed wiring boards and is used in many flame-retardant surface-mounted adhesives.2 It is manufactured by several producers and is priced as a commodity product. 

The moisture resistance properties of filled molding compounds are enhanced by the treatment of the fillers with silane adhesion promoters prior to compounding. Silane promoters on wollastonite fillers in thermoplastic polyester molding compounds (50 percent filled) will improve the flexural strength after 16 h in 50°C water by as much as 40 percent. Silane-treated silica fillers have been found to significantly increase the moisture resistance of epoxy adhesives used in the electronics industry for chip, surface-mounted, and printed-circuit processes.8... 

SMT has been used in the hybrid industry since the late 1950s. Nowadays, however, SMT implies the assembly of surface mountable components onto organic substrates such as glass epoxy and phenolic paper. Surface mounting makes more efficient use of substrate area through the use of smaller components and the elimination of large PTH s, because only smaller via holes will be required. As the IC complexity, customization and pin count increase there will be no alternative interconnection technology that can cope. 

Single part epoxy presents another option. Some materials, such as surface mount adhesives, have the curing catalyst locked in a phase change material that is released with heat. Cure temperatures range from 100 to 150°C. The material supplier controls the mixing process, and these materials have excellent shelf life. 

Surface-mount adhesives 35-50% epoxy resin, 1-10% amine or polyamine curing agent, and 10-30% mineral filler and thixotrope Mondur MC/castor oil and castor oil polyols (>60%), filler 5%) Eccobond 125F (Henkel), Epo-Tek 70E-4 (Epoxy Technology), Epi-bond 7275 (Cookson Electronics) Flexobond 442 (Bacon Industries)... 

Adhesives used for screen or stencil printing in surface-mount applications are generally electrically insulative types whose functions are mechanical attachment and thermal dissipation. However, electrically conductive, silver-filled epoxies have been used for many years as ohmic contact adhesives to interconnect bare-chip devices in hybrid microcircuits and are used as solder replacements for surface mounting of components on printed-circuit boards. Regardless of their... 

Surface-mount adhesives, silver epoxy, solder paste, and comer and edge bonding... 

Values are averages of seven batches of Aptek Laboratories surface-mount epoxy adhesive DIS-A-PASTE 2311 PMF. Source Aptek Labs. Inc.)... 

Epoxy, capillary N/A Surface-mount devices to Hand, time-pressure. Reworkable CSP, flip... 

Many aerobic formulations can be heat cured, but only between two surfaces. Table 1 shows the heat curing properties in an adhesive used to fix surface mount devices onto printed circuit boards compared to a typical epoxy and a typical anaerobic formulation used for the same purpose. 

Strips are applied directly on the surface of a structure that is pretreated, e.g. by grinding or sand-blasting, using a two-component epoxy adhesive. Another technique is the so-called near surface mounted reinforcement (NSMR), which means that the strips are embedded into slits in the... 

Surface- mount adhesives DGEBA Resin (GY 6010, DER 331, Shell 828) 40-50% Amine epoxy adduct or polyamide (Versamide , Ancamide, Aradur , etc.) 20-30% Mineral filler and thixotrope 12-25% Amicon 125 D3, Amicon E 6752, Epo-Tek 70E-4 Chipbonder series (Loctite), Epi-bond 7275 (Vantico)... 

Electrically conductive adhesives, primarily silver-filled epoxies, are finding uses as replacements for solder in surface-mounting components on printed-circuit boards and in flip-chip attachments. There are several driving forces for this application, a major one being the trend to eliminate lead and tin-lead solders because they may be health hazards. Also associated with the use of solder, is the need to eliminate ozone-depleting solvents presently used to clean and remove flux residues. Electrically conductive polymer... 

Microfluidic Boards Microfluidic board interconnection technologies seek to mimic the electronic printed circuit board for ease of use, reliability, and versatility. In microfluidic board technologies, the substrate contains the passive microfluidic channels and reservoirs, with active components (e.g., sensors, valves) mounted on top (e.g.. Ref. [2]) (see Fig. 1) similarly to electronic components mounted on a printed circuit board (PCB) or multichip modules (MCM) in surface-mount technologies (SMT). Electronic coimections between components are provided on top of the board, while fluidic interconnection is usually provided in the board material itself. Microfluidic circuit boards can be made from a variety of materials, including silicon, glass, and polymers, e.g., polydimethylsiloxane (PDMS), epoxy, or polymethyl methacrylate (PMMA). Microfluidic boards can be as simple... 

An alternative or complementary technique based on near surface mounted reinforcements and called NSM consists in inserting FRP rods with an epoxy adhesive or cement grout into grooves cut in the concrete member (De Lorenzis and Teng, 2007). 

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