Copper filling

FIGURE 17.30 Copper-filled failure-induced pitting after Ta CMP. 

Consider a 15-cm X 20-cm epoxy glass laminate (k = 0.17 W/m "C) whose thickness is 0.13 cm. In order to reduce the thermal resistance across its thickness, cylindrical copper fillings (k - 386 W/ni - °C) of 0.05 cm diameter are to be planted throughout the board, with a centei-io-center distance of 0.15 cm. Determine the new value of the thermal resistance of the epoxy board for beat conduction across its thickness as a result of this modification. Ansv/en 0.00128 C/V/... 

The reason why gum arabic is used as binder, lies in the fact that the match dries relatively quickly and becomes quite stiff and easily handled, i.eo easily inserted into a paper tube. Nitrocellulose with an organic solvent Can also be used as the binder, but in this case the fuse is too soft and too flexible to be handled. Prepare a double bottomed water bath made of copper. Fill the outer vessel with hot water and heat it with a safe heater which generates neither flame nor sparks. The inner vessel of the bath gives the space for pasting the slurry on to the strands. Pass the strands through a small hole at one side of the vessel, round two reels which are situated at the bottom of the inner vessel and then through a funnel-like outlet which is placed on the opposite side(Fig.72). 

Experimental method to measure the effectiveness of an explosive. The radial expansion on detonation of a metallic cylinder (usually copper) filled with a high explosive is observed. A streak camera or a laser method might be used. The detonation velocity is determined simultaneously, using for example time-of-arrival pins. The -> Equation of State (EOS) which is often the Jones-Wilkins-Lee (JWL) EOS of the detonation products is derived using Gurney theory. 

Nanoparticles of silver and carbon are also being studied as replacements for copper or gold plating or for copper filling of microvias in interconnect substrates. ... 

Electrical-andjor thermal-conducting adhesives [1,9]. The epoxies and acrylates described above are filled with metal powders to get electrical-conducting adhesives. For special applications polyimide and silicone adhesives are used also. Since the metallic particles must touch each other inside the resins to reach a sufficient level of conductivity, a metal content of 70 to 80 wt % is necessary. Silver is the metal generally used, since specific resistances of the filled adhesives down to about 10 " S2cm can be achieved (metallic silver has a specific resistance of 1.6 x 10 S2cm). Using other metals, such as copper or nickel, the accessible electrical conductivity is too small. On the other side, copper-filled resins show good thermal conductivity and are therefore used for such... 

Comalloy 940 Polypropylene 50 % copper filled, PP Comalloy IntL Corp. 

Lin and Chiu [55] studied the effects of silver or copper particle composition (silver coated or uncoated copper), on particle shape (flake or spherical), particle size and oxidation temperature on the electrical properties of copper-filled epoxy resin electrically conductive adhesives. They also studied pressure dependent conduction behaviour of compressed copper particles. The silver-coated copper particles showed significantly greater oxidation resistance than un-coated copper particles because the... 

Pourabas and Peyghambardoost [53] showed that copper filled epoxy resin composite had electrical conductivity properties. Afzal and co-workers [104] studied the electrical properties of PANI/silver nanocomposites. The silver nanoparticles in PANI reduced the charge trapping centres and increased the conducting channels of the polymer. 

Zacharatos F, Nassiopoulou AG (2008) Copper-filled macroporous Si and cavity underneath for microchannel heat sink technology. Phys Stat Sol (a) 205 2513-2517... 

Some measurements of this property have been made in a range of electrically conducting polymers. These include epoxy resin/polyaniline-dodecylbenzene sulfonic acid blends [38], polystyrene-black polyphenylene oxide copolymers [38], semiconductor-based polypyrroles [33], titanocene polyesters [40], boron-containing polyvinyl alcohol [41], copper-filled epoxy resin [42], polyethylidene dioxy thiophene-polystyrene sulfonate, polyvinyl chloride, polyethylene oxide [43], polycarbonate/acrylonitrile-butadiene-styrene composites [44], polyethylene oxide complexes with sodium lanthanum tetra-fluoride [45], chlorine-substituted polyaniline [46], polyvinyl pyrolidine-polyvinyl alcohol coupled with potassium bromate tetrafluoromethane sulfonamide [47], doped polystyrene block polyethylene [38, 39], polypyrrole [48], polyaniline-polyamide composites [49], and polydimethyl siloxane-polypyrrole composites [50]. 

Fig. 10.9. Example of copper coil produced by microelectroforming using a microstructured glass template, (left) Copper coil after the removal of the glass template, (right) copper filled glass template...

In general, conductive adhesive pastes are formulated by mixing polymeric resins (such as epoxies, silicones, and polyimides) and highly conductive metallic fillers The most popular combination has been silver (Ag) particles in epoxy resin [2,3,4,5]. The formulas and preparation techniques for conductive adhesives are still imder development. Nickel, with its lower cost than silver, and its comparatively less oxidation and better thermal stability than copper, offers an appropriate alternative to silver for ICA s, while the copper-filled systems may be unstable after exposure to elevated temperatures due to oxide growth on the particle surfaces [6]. 

---