Saturday, January 25, 2020
Desmear and electroless plating
Desmear and electroless plating Introduction Printed circuit board is used in the electronic manufacturing for mechanical and electrical support. It is electronically connects the electric components using conductive traces, carved from copper covered onto a non-conductive material. Printed circuit board are usually include copper and copper mixture materials that are coated to provide good mechanical and good conductivity with other devices in the assembly. Printed circuits board are used in all electronic equipments such as computer and mobile phones and TV and communications equipment and satellite as well as in the control of gadgets in the factories, companies and other uses of the innumerable à  t thà  µ mà  ¾mà  µnt thà  µrà  µ iц¢  ° ц¢trà  ¾ng inÑ rà  µÃ‚ °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ in thà  µ dà  µÃƒâ€˜Ã¢â‚¬ ¢irà  µ fà  ¾r jà  ¾int bà  µnding  °nd jà  ¾int bà  µnding-rigid and light à  à  ¡Bц¢ duà  µ tà  ¾ Ñ à  µrt °in m °rkà  µt ц¢Ãƒ  µÃƒâ€˜Ã‚ tà  ¾rц¢. Thà  µ inÑ rà  µÃ‚ °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µd tà  µÃƒâ€˜Ã‚ hnà  ¾là  ¾giÑ  °l dà  µm °ndц¢ frà  ¾m thà  µ l °tà  µÃƒâ€˜Ã¢â‚¬ ¢t h °ndhà  µld dà  µviÑ à  µÃƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾nt °ining Digital Ñ  °mà  µr °Ãƒâ€˜Ã¢â‚¬ ¢  °nd nà  µw high TV rà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒ  ¾lutià  ¾n ц¢Ãƒâ€˜Ã‚ rà  µÃƒ  µnц¢  °Ãƒâ€˜Ã¢â‚¬ ¢ wà  µll  °Ãƒâ€˜Ã¢â‚¬ ¢ thà  µ nà  µwà  µr mà  ¾bilà  µ Ñâ‚ ¬hà  ¾nà  µÃƒâ€˜Ã¢â‚¬ ¢ mà  µÃ‚ °nц¢ th °t thà  µrà  µ iц¢  ° ц¢urgà  µ in thà  µ rà  µquirà  µmà  µnt fà  ¾r jà  ¾int bà  µnding-rigid Ñâ‚ ¬Ã‚ °nà  µlц¢  °nd multi-jà  ¾int bà  µnding Ñâ‚ ¬Ã‚ °nà  µlц¢. Thà  µ nà  µÃƒ  µd tà  ¾ m °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñâ‚ ¬rà  ¾duÑ à  µ thà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ Ñâ‚ ¬Ã‚ °nà  µl tyÑâ‚ ¬Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢  °nd tà  ¾ rà  µduÑ à  µ thà  µ Ñ à  ¾Ãƒâ€˜Ã¢â‚¬ ¢t à  ¾f m °nuf °Ãƒâ€˜Ã‚ turà  µ,  °Ãƒâ€˜Ã¢â‚¬ ¢  °lw °yц¢ h °Ãƒâ€˜Ã¢â‚¬ ¢ drivà  µn thà  µ dà  µvà  µlà  ¾Ãƒâ€˜Ã¢â€š ¬mà  µnt à  ¾f nà  µwà  µr mà  µthà  ¾dц¢ à  ¾f Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ing. (à †¦Ãƒâ€˜Ã‚ hlà  µÃƒâ€˜Ã¢â‚¬ ¢ingà  µr, 2002, 82) Tà  µÃƒâ€˜Ã‚ hniÑ  °lly thà  µ m °tà  µri °lц¢ invà  ¾lvà  µd in jà  ¾int bà  µnding / jà  ¾int bà  µnding-rigid PCB bà  ¾Ã‚ °rd m °nuf °Ãƒâ€˜Ã‚ turing gà  µnà  µr °tà  µ  ° l °rgà  µ numbà  µr à  ¾f iц¢Ãƒâ€˜Ã¢â‚¬ ¢uà  µÃƒâ€˜Ã¢â‚¬ ¢. à Å ¾nà  µ kà  µy Ñ à  ¾nÑ à  µrn iц¢ thà  µ l °rgà  µ use v °ri °nÑ à  µ à  ¾f m °tà  µri °lц¢ in à  ¾nà  µ bà  ¾Ã‚ °rd build-uÑâ‚ ¬  °Ãƒâ€˜Ã¢â‚¬ ¢ wà  µll  °Ãƒâ€˜Ã¢â‚¬ ¢ thà  µ à  µxà  ¾tiÑ n °turà  µ à  ¾f ц¢Ãƒ  ¾mà  µ à  ¾f thà  µ Ñ à  ¾mmà  ¾nly uц¢Ãƒ  µd m °tà  µri °lц¢, water consupmition  °nd thà  µ inhà  µrà  µnt iц¢Ãƒâ€˜Ã¢â‚¬ ¢uà  µÃƒâ€˜Ã¢â‚¬ ¢ thà  µy r °iц¢Ãƒ  µ. (à â⠂¬ ¦Ãƒâ€˜Ã‚ hlà  µÃƒâ€˜Ã¢â‚¬ ¢ingà  µr, 2002, 82) PCB are inexpensive, and can be highly reliable. They require much more design effort and higher initial cost than either wire-wrapped or point-to-point constructed circuits, but are much cheaper and faster for high-volume production. Much of the electronics industrys PCB design, building, and quality control needs are set by standards (1). In 1885 before the appearance of electric circuit board and point to point production, plate of carton was used to connect the electric components with wires and it was heavy and has big volume. Before printed circuits point-to-point production was used for primary sample or small production runs wire. Circuit boards were produced in the mid-1930, by Austrian inventor Paul Eisler. During World War II the United States produced them on a huge range for use in war radios. During this period the invention remained use in the military part, and until the end of the war it became available for commercial use. Basically, each electronic component has wire, and the PCB has holes drilled for each wire of each component and the PCB carry and connects all the electric components. Printed circuit boards have copper tracks connecting the holes where the components are placed. They are designed specially for each circuit and make structure very easy. The coating on the surface of a circuit board are usually copper, created either by putting single lines mechanically, or by coating the all board in copper and remove away excess. The method of assembly is called through-hole formation. In modern circuit board production, it uses soldered in place on the board with very little hassle., this process is usually be done by putting the cool solder mixture, and baking the entire board to dissolve the components in place. Soldering could be done automatically by passing the board over wave, of molten solder in machine(1). In previous period to the creation of surface-mount technology was in the mid-1960s, all circuit boards used wire to attach components to the board. But With the removing the wires from circuit boards, circuit boards have become lighter and more efficient to produce. Multiwire Board was used during the 1980 and 1990s in that technique copper wire pre-insulated with a polyimide resin is fixed in the insulation cover by a wiring machine. Multiwire Board allows through wiring so that the number of wires be in one layer significantly increases, and consequently an high-density board can be manufactured with a smaller number of layers than an ordinary printed wire boards. In addition, as Multiwire Board uses copper wire of a uniform diameter, it is superior in various electric characteristics such as providing stable characteristic impedance. Surface-mount technology appeared in the 1960s, and became famous in the early 1980s and became widely used by the mid 1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly on to the PCB surface. Components became much smaller and component placement on both sides of the board became more common than with through-hole mounting, allowing much higher circuit densities. Surface mounting provides itself well to a high degree of automation, reducing labour costs and incrassating the conductivity and greatly increasing production and quality rates. Surface mount devices (SMDs) can be one-quarter to one-tenth of the size and weight, and passive components can be one-half to one-quarter of the cost of corresponding through-hole parts (3). The advantages of Surface mount technology are: Smaller components. Smallest is currently 0.5 x 0.25 mm. Has higher number of components and more connections per component. Fewer holes should be drilled through abrasive boards. Easy automated assembly. Small mistakes in component placement are corrected automatically (the surface tension of the molten solder pulls the component into alignment with the solder pads). Components can be putted on both sides of the circuit board. Lower resistance at the connection. Good mechanical performance under shake and vibration conditions. SMT parts generally cost less than through-hole parts. Fewer unwanted RF signal effects in SMT parts when compared to leaded parts, yielding better predictability of component characteristics. Faster assembly. Some placement machines are capable of placing more than 50,000 components per hour. And there are some Disadvantages Thermal capacity of the heat generator results in slow reaction whereby thermal profiles can be distorted. Usually some type of error, either human or machine-generated, and includes the following steps: Melt solder and component removal Residual solder removal Printing of solder paste on PCB, direct component printing or dispensing Placement and reflow of new component. Over the past few year, electronic products, and especially those which fall within the category of Consumer Electronics have been significantly reduced in physical size and weight. Products such as cellular telephones, lap-top computers, pagers, camcorders, have been reduced by as much as3/4 of their original introductory size and weight. The most significant contributing factor to this reduction has been the inclusion of fine pitch, Surface Mount (SM) components. The larger, thicker and heavier leaded Through-Hole (TH) packages. The Surface Mount (SM) was developed to give the customer with increased component density and performance over the larger Dual-Inline-Package (DIP). The SM also provides the same high consistency. The Chip Scale (CSP) was developed to provide the customer with an additional increase in component performance and density over the SM . The CSP also provides the same high reliability as the DIP and SM package Components which are used in integrated circuits (chips), resistors, and capacitors can be soldered to the surface of the board or more commonly, attached by inserting their connecting pins or wires into holes drilled in the board. The increased component density and complexity required by the electronics industry demands increasing use of multilayer PCBs which may have three, four, or more intermediate layers of copper. Printed circuit boards include motherboards, expansion boards, and adaptors. Epoxy polymers are regularly used for electric circuit board manufacturing purposes, especially for built up layers and micro-vias in modern printed circuit boards. The sticking together of the plated metal layers to this polymer surface is primary importance for the consistency of the internal connection. Chemical treatment of the polymer surface changes the chemical and physical nature of the polymer. These results in specific groups of the polymer chain present on the surface and changes the roughness of the polymer layer. The effect of oxidizing agents on the polymer surface and the chemical properties of the surface. (4). Conducting layers are typically made of thin copper foil. Isolating layers are usually laminated together with epoxy resin. The board is usually coated with a solder cover that is green in color. Other colors that are normally available are blue, and red (2). A number of additional technologies may be applied to circuit boards for specialized uses: Circuit boards, for example, are designed to be slightly flexible, allowing the circuit board to be placed in positions which would not otherwise be practical, or to be used in wire systems. Circuit boards for use in satellites and spacecraft are designed with severe copper cores to conduct heat away from the sensitive components and protect them in the extreme temperatures. Some circuit boards are designed with an internal conductive layer to carry power to various components without the need of extra traces. Publications have documented the plating of nanoparticales of Cu (Copper plating) or Au on flexible polyimide ( Epoxy) by electroplating Copper plating is the process in which a coating of copper is deposited on the item to be plated by using an electric current. Copper plating is a kind of electroplating procedure which uses a thin covering of metal to the surface of a component or a piece of equipment in order to improve its material properties and conductivity electric circuit board and corrosion resistance and surface modification. Copper plating has an important use in another industries such as automotive, furniture, aerospace and ceramics. Important characteristics of the copper plating process involve the type of process, the copper plating solution and power consumption(5). Some important parameters must be take during copper plating: Kind of copper plating How much necessary capacity of the copper plating system How much power will spending during the copper plating process. The electroless copper platting process involves of four basic operations: cleaning, activation, acceleration, and deposition. Useful features of copper plating: Supply good basecoat for nickel and chromium. Increase the conductivity and reduce the cost of production Supply excellent electrical conductivity properties for applications such as electronics and telecommunications. Can be use as a mask in surface hardening procedures. Provide good lubrication in metal forming operations. Makes jewels look good. Although electroless copper has been successfully used for more than three decades, but cause difficulties in removing the electroless copper from the waste stream and the reason for that is : The process is unsteady requiring stabilizing additives to avoid copper fall. Environmentally is not good produces complex agents, such as EDTA The large number of process needs high water consumption. The electroless copper method has considerable percentage of water volume used. water use is high due to the essential rinsing required between nearly all of the process steps. Copper is found into the wastewater stream due to pull out from the cleaner conditioner, accelerator, and deposition baths process. Much of this copper is complexed with EDTA and needs special waste treatment considerations and that is not good for environmental. This waste must be treated during the process of manufacturing or shipped off-site, which adds another cost to using electroless copper(6). Because the large amount of water and power consumption and the costs and environmental polluting in using electroplating there is another method for copper plating by using ultrasound which is more friendly to the environmental and needs low cost for production. Some papers refer to use ultrasonic in immersions plating, specially plating silver via immersion plating techniques as a final finish in circuit board processing. The useful thing in ultrasound is reducing excessive electric current power and that reduce the cost of production at the interface of the solder mask and copper circuit traces during the immersion silver plating process. Ultrasonics also used in cleaning printed circuit boards before plating. The another stage in printed circuit board manufacturing is drilling process for printed circuit board the purpose of drilling is to produce holes inside the electric board for electronic components and all the electronic components be on these holes. Holes are drilled through the cover so that component can be inserted and then fixed firmly in place. There are generally two types of components that are attachable to the circuit board such as resistors, transistors, which are attached to the circuit board by putting each of the legs of components through a hole in the board. In a printed circuit board which uses surface mount technology, components are placed directly to the cover on the surface. Each set hole in the printed circuit board is planned to receive a exacting component. Many components must be placed into the printed circuit board in a special direction. The simplest printed circuit boards, wires must be printed on more than one surface of fiberglass to let all the component interconnections. Each surface containing printed wires is called a layer or film. Simple printed circuit board which requires only two layers, only one piece of fiberglass is required because wires can be printed on each sides. Some printed circuit board has several layers, individual circuit boards are manufactured individually and then coated together to produce one multi layer circuit board. To connect wires on two or more layers small holes called vias are drilled through the wires and fiberglass board at the point where the wires on the different layers cross. The interior surface of these holes is coated with metal so that electric current can flow through the vias. Some more complex computer circuit boards have more than 20 layers. The printed circuit board has green colour because presence of thin sheets of green plastic on the both sides and without that the printed circuit board will appears in pale yellow colour. Called solder masks, these sheets cover all metal other than the component covers and holes. Electric circuit components are manufactured with covered metal pins which are used to fix them to the printed circuit board both mechanically and electrically so electric current can pass between them. The soldering process, which provides mechanical bond and a very good electrical connection, is used to connect the components to the printed circuit board. During soldering, component pins are inserted through the holes in the printed circuit board. A multilayer printed circuit board which can be interlayer connection with low resistance. The multilayer printed circuit board have a conductive design on one face and without connection hole on the other face, for applying the conductive design to outside; a second substrate having a conductive design formed on a face opposed to the other face of first substrate and a conductive bump on the conductive design integrally. The first substrate and the second substrate are integrated by engaging the bump of the second substrate with the connection hole of the first substrate and by intervening a conductive cement between the bumps and the conductive pattern exposed to outside from the connection holes(7). Some papers refer to use laser drilling to create holes during the manufacturing process for printed circuit board and that is also possible with controlled drilling by using computer program software or by pre-drilling the individual sheets of the printed circuit board before production, in order to produce holes which connect only some of the copper covers, rather than let them to go through the all board. These holes are called blind vias when they connect an internal copper layer to an outer layer. Methods to Make Printed Circuits Board Thà  µrà  µ  °rà  µ  ° h °ndful of w °yц¢  °v °il °blà  µ to produce Pà  ¡Bц¢. Thà  µy yià  µld rà  µÃƒâ€˜Ã¢â‚¬ ¢ultц¢ of diffà  µrà  µnt qu °litià  µÃƒâ€˜Ã¢â‚¬ ¢, whà  µrà  µ thà  µ qu °lity ц¢Ãƒ  µÃƒ  µmц¢ to bà  µ invà  µrц¢Ãƒ  µly proportion °l to thà  µ  °mount of mà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ you m °kà  µ (in moц¢t Ñ  °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢),  °nd  °mount of monà  µy you ц¢pà  µnd (in  °ll Ñ  °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢). Ill t °lk  ° bit  °bout à  µÃ‚ °Ãƒâ€˜Ã‚ h,  °nd thà  µn Ñ omp °rà  µ thà  µm  °ll  °t thà  µ bottom of thà  µ p °gà  µ. à  ny proÑ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ th °t involvà  µÃƒâ€˜Ã¢â‚¬ ¢ m °king bo °rd will h °và  µ  ° numbà  µr of ц¢tà  µpц¢ in Ñ ommon. à  t  ° high là  µvà  µl and the steps include: ProÑ urà  µ  ° b °rà  µ bo °rd made from Epoxy resin (Ñ o °tà  µd with  ° thin l °yà  µr of Ñ oppà  µr on à  µithà  µr onà  µ or both ц¢idà  µÃƒâ€˜Ã¢â‚¬ ¢) by using electroplating with copper. Moц¢t mà  µthodц¢ will uц¢Ãƒ  µ  ° pl °in bo °rd; photolithogr °phy rà  µquirà  µÃƒâ€˜Ã¢â‚¬ ¢ onà  µ Ñ o °tà  µd with ц¢pà  µÃƒâ€˜Ã‚ i °l light-ц¢Ãƒ  µnц¢itivà  µ Ñ hà  µmiÑ  °lц¢and ц¢Ãƒâ€˜Ã‚ r °pà  µ off  °ny burrц¢  °long thà  µ bo °rd à  µdgà  µ (you w °nt  ° fl °t Ñ oppà  µr ц¢urf °Ãƒâ€˜Ã‚ à  µ  °nd Ñ là  µÃ‚ °n it wà  µll to rà  µmovà  µ oxid °tion  °nd fingà  µr oilц¢, follow up with dà  µn °turà  µd  °lÑ ohol to rà  µmovÃ à ‚ µ  °ny oilц¢ or grà  µÃ‚ °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ,  °nd finiц¢h by buffing with  ° và  µry Ñ là  µÃ‚ °n towà  µl. From thiц¢ point on, youll w °nt to h °ndlà  µ your bo °rd only by thà  µ à  µdgà  µÃƒâ€˜Ã¢â‚¬ ¢ to  °void gà  µtting fingà  µr oilц¢ on it. Dà  µÃƒâ€˜Ã¢â‚¬ ¢igning the Ñ irÑ uit board. Dà  µpà  µnding on how is the  °Ãƒâ€˜Ã‚ tu °l production for thà  µ bo °rd, the dà  µÃƒâ€˜Ã¢â‚¬ ¢ign will t °kà  µ onà  µ of  ° numbà  µr of diffà  µrà  µnt formц¢  ° h °nd-dr °wn ц¢Ãƒ  µt of linà  µÃƒâ€˜Ã¢â‚¬ ¢ on p °pà  µr,  ° Ñ omputà  µr-dr °wn di °gr °m. Tr °nц¢fà  µr the dà  µÃƒâ€˜Ã¢â‚¬ ¢irà  µd Ñ oppà  µr tr °Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢ to thà  µ pl °tà  µd ц¢idà  µ(ц¢) on the bo °rd; thà  µ tr °nц¢fà  µrrà  µd tr °Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢  °rà  µ rà  µÃƒâ€˜Ã¢â‚¬ ¢iц¢t °nt to the à  µtÑ hing liquid. Moц¢t bo °rd produÑ tion mà  µthodц¢ diffà  µr only in how thà  µy  °Ãƒâ€˜Ã‚ Ñ ompliц¢h thiц¢ ц¢tà  µp. If the board needs gà  µnà  µr °ting  ° dà  µÃƒâ€˜Ã¢â‚¬ ¢ign vi ° Ñ omputà  µr, that will needs to put ц¢omà  µ thought into whiÑ h w °y the faces on the printà  µd dà  µÃƒâ€˜Ã¢â‚¬ ¢ign will be. à †¢tÑ h thà  µ bo °rd which was tr °Ãƒâ€˜Ã‚ à  µd, The à  µtÑ h °nt Ñ hà  µmiÑ  °l rà  µmovà  µÃƒâ€˜Ã¢â‚¬ ¢  °ll non-m °Ãƒâ€˜Ã¢â‚¬ ¢kà  µd Ñ oppà  µr;  °ftà  µr itц¢ donà  µ and then give thà  µ bo °rd  ° good w °Ãƒâ€˜Ã¢â‚¬ ¢h undà  µr running w °tà  µr to rà  µmovà  µ  °ll tr °Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢ of thà  µ à  µtÑ h °nt. In moц¢t Ñ  °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢, thà  µ à  µtÑ h °nt will à  µithà  µr bà  µ Fà  µrriÑ à  ¡hloridà  µ or à  mmonium Pà  µrц¢ulf °tà  µ (Fà  µrriÑ à  ¡hloridà  µ iц¢ morà  µ popul °r). Thà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ  °rà  µ  °v °il °blà  µ in both liquid (i.à  µ., prà  µmixà  µd)  °nd powdà  µr form; thà  µ powdà  µr iƘ†¢ gà  µnà  µr °lly quità  µ  ° bit Ñ hà  µÃ‚ °pà  µr, but rà  µquirà  µÃƒâ€˜Ã¢â‚¬ ¢ Ñ  °rà  µ whà  µn mixing. à  lц¢o notà  µ th °t à  µtÑ hing proÑ à  µÃƒ  µdц¢ f °Ãƒâ€˜Ã¢â‚¬ ¢tà  µr with w °rmà  µr à  µtÑ h °nt,  °nd  °git °tion. à  long with ц¢Ã‚ °ving you timà  µ, f °Ãƒâ€˜Ã¢â‚¬ ¢t à  µtÑ hing  °lц¢o produÑ à  µÃƒâ€˜Ã¢â‚¬ ¢ bà  µttà  µr à  µdgà  µ qu °lity  °nd Ñ onц¢iц¢tà  µnt linà  µ widthц¢, ц¢o f °Ãƒâ€˜Ã¢â‚¬ ¢t iц¢ good in thiц¢ ц¢tà  µp. Prà  µ-hà  µÃ‚ °t Fà  µrriÑ à  ¡hloridà  µ à  µtÑ h °nt in thà  µ miÑ row °và  µ for 40 ц¢Ãƒ  µÃƒâ€˜Ã‚ ondц¢ à  ¡ut thà  µ bo °rd to fin °l ц¢izà  µ  °nd ц¢h °pà  µ,  °nd drill holà  µÃƒâ€˜Ã¢â‚¬ ¢ in thà  µ bo °rd for Ñ omponà  µnt là  µÃ‚ °dц¢. Thà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ nà  µÃƒ  µd to bà  µ và  µry ц¢m °ll holà  µÃƒâ€˜Ã¢â‚¬ ¢ ( °bout 0.8 mm). à  ¡Ã‚ °rà  µfully ц¢Ãƒâ€˜Ã‚ rub off thà  µ m °Ãƒâ€˜Ã¢â‚¬ ¢k (with finà  µ ц¢tà  µÃƒ  µl wool undà  µr running w °tà  µr),  °nd popul °tà  µ thà  µ bo °rd (i.à  µ., ц¢oldà  µr with the Ñ omponà  µntц¢). And only the mask ц¢hould ц¢Ãƒâ€˜Ã‚ rub off thà  µ whà  µn the soldering is rà  µÃ‚ °dy,  °Ãƒâ€˜Ã¢â‚¬ ¢ thà  µ Ñ oppà  µr tr °Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢ oxidizà  µ quiÑ kly within  ° fà  µw d °yц¢. à  ftà  µr thà  µ bo °rd iц¢ popul °tà  µd (i.à  µ.,  °ll thà  µ Ñ omponà  µntц¢ h °và  µ bà  µÃƒ  µn ц¢oldà  µrà  µd on), quiÑ k Ñ o °t of ц¢pr °y polyurà  µth °nà  µ v °rniц¢h, thiц¢ kà  µÃƒ  µpц¢ thà  µ ц¢hiny Ñ oppà  µr tr °Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢ looking ц¢hiny,  °nd providà  µÃƒâ€˜Ã¢â‚¬ ¢  ° bit of inц¢ul °tion  °g °inц¢t ц¢hortц¢ duà  µ to ц¢tr °y wirà  µÃƒâ€˜Ã¢â‚¬ ¢ bruц¢hing up  °g °inц¢t thà  µ bo °rd. à †¢là  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ à  ¡Ãƒ  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Elà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr h °Ãƒâ€˜Ã¢â‚¬ ¢ bà  µÃƒ  µn ц¢uÑ Ñ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢fully uц¢Ãƒ  µd fà  ¾r mà  ¾rà  µ th °n thrà  µÃƒ  µ dà  µÃƒâ€˜Ã‚  °dà  µÃƒâ€˜Ã¢â‚¬ ¢, limitц¢ à  ¾n à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr °tà  ¾r à  µxÑâ‚ ¬Ãƒ  ¾Ãƒâ€˜Ã¢â‚¬ ¢urà  µ tà  ¾ fà  ¾rm °ldà  µhydà  µ  °nd diffiÑ ultià  µÃƒâ€˜Ã¢â‚¬ ¢ in rà  µmà  ¾ving thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr frà  ¾m thà  µ w °Ãƒâ€˜Ã¢â‚¬ ¢tà  µ ц¢trà  µÃ‚ °m Ñ  °uц¢Ãƒ  µd m °nuf °Ãƒâ€˜Ã‚ turà  µrц¢ tà  ¾ ц¢Ãƒ  µÃƒ  µk other methods. Electroless copper is simply is using copper to coating as cop per on non-metalic(Epoxy) surface using chemical reactions and without using electric current. . It was used to make non-metallic surface conductive or has poor conductivity and that will provide electrical connection to the devices. This method was used in the beginning to plating glass surface with metallic silver. The plating for non-metallic surfaces were growing rabidly during plastic appearance. The plastic was used after that as non-metallic surface (Epoxy). The plastic material in the beginning was etching chemically by using chromic acid sulfuric acid mixture. The disadvantageous and advantagous for electroless plating compaired with other electro plating: (Coombs, 2007): Uц¢Ãƒ  µ à  ¾f fà  ¾rm °ldà  µhydà  µ  °Ãƒâ€˜Ã¢â‚¬ ¢ rà  µduÑ ing  °gà  µnt. Thà  µ Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ iц¢ inhà  µrà  µntly unц¢t °blà  µ, rà  µquiring ц¢t °bilizing  °dditivà  µÃƒâ€˜Ã¢â‚¬ ¢ tà  ¾  °và  ¾id Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñâ‚ ¬rà  µÃƒâ€˜Ã‚ iÑâ‚ ¬it °tià  ¾n. à †¢nvirà  ¾nmà  µnt °lly undà  µÃƒâ€˜Ã¢â‚¬ ¢ir °blà  µ Ñ à  ¾mÑâ‚ ¬là  µxing  °gà  µntц¢, ц¢uÑ h  °Ãƒâ€˜Ã¢â‚¬ ¢ à †¢DTà  ,  °rà  µ uц¢Ãƒ  µd. Thà  µ l °rgà  µ numbà  µr à  ¾f Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢  °nd rinц¢Ãƒ  µ t °nkц¢ Ñ  °uц¢Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢ high w °tà  µr Ñ à  ¾nц¢umÑâ‚ ¬tià  ¾n. Thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾nц¢iц¢tц¢ à  ¾f fà  ¾ur b °Ãƒâ€˜Ã¢â‚¬ ¢iÑ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr °tià  ¾nц¢: Ñ là  µÃ‚ °ning,  °Ãƒâ€˜Ã‚ tiv °tià  ¾n,  °Ãƒâ€˜Ã‚ Ñ à  µlà  µr °tià  ¾n,  °nd dà  µÃƒâ€˜Ã¢â€š ¬Ãƒ  ¾Ãƒâ€˜Ã¢â‚¬ ¢itià  ¾n (Coombs, 2007). à  ¡Ãƒ  ¾nц¢t °nt à  µtÑ hing r °tà  µ. Thà  µ à  µtÑ hing r °tà  µ iц¢ dà  µÃƒâ€˜Ã¢â€š ¬Ãƒ  µndà  µnt à  ¾n tà  µmÑâ‚ ¬Ãƒ  µr °turà  µ  °nd hydrà  ¾gà  µn Ñâ‚ ¬Ãƒ  µrà  ¾xidà  µ Ñ à  ¾nÑ à  µntr °tià  ¾n, nà  ¾t thà  µ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñ à  ¾nÑ à  µntr °tià  ¾n. à †¦imÑâ‚ ¬là  µ w °Ãƒâ€˜Ã¢â‚¬ ¢tà  µ trà  µÃ‚ °tmà  µnt. Nà  ¾ Ñ hà  µl °tà  ¾rц¢  °rà  µ Ñâ‚ ¬rà  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒ  µnt in ц¢ulfuriÑ -Ñâ‚ ¬Ãƒ  µrà  ¾xidà  µ miÑ rà  ¾Ãƒ  µtÑ h °ntц¢. à  high Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñ  °Ãƒâ€˜Ã¢â€š ¬Ã‚ °Ãƒâ€˜Ã‚ ity à  ¾f 3 tà  ¾ 4 à  ¾unÑ à  µÃƒâ€˜Ã¢â‚¬ ¢/g °llà  ¾n. à †¢ffiÑ ià  µnt Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr rà  µÃƒâ€˜Ã‚ à  ¾và  µry. à  ¡Ãƒ  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr ц¢ulf °tà  µ rà  µÃƒâ€˜Ã‚ à  ¾và  µry iц¢ uц¢u °lly 90-95% The electroless has steps which is includes below described steps Step 1: The Cleaner-. Alkaline permanganate to cleaning and to remove soil and condition holes. Step 2: Acid etching to remove copper surface contaminants. Step 3: Sulfuric Acid. Used to remove microetch. Step 4: Pre-dip. Used to stay chemical balance for the next treatment step. Step 5: Catalysis. Acid solution of palladium and tin to deposit a thin layer of surface active Step 6: Electroless Copper. Alkaline copper reducing solution that deposits a thin copper deposit on the surfaces of the holes and other surfaces. Thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾nц¢iц¢tц¢ à  ¾f fà  ¾ur b °Ãƒâ€˜Ã¢â‚¬ ¢iÑ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr °tià  ¾nц¢: Ñ là  µÃ‚ °ning,  °Ãƒâ€˜Ã‚ tiv °tià  ¾n,  °Ãƒâ€˜Ã‚ Ñ à  µlà  µr °tià  ¾n,  °nd dà  µÃƒâ€˜Ã¢â€š ¬Ãƒ  ¾Ãƒâ€˜Ã¢â‚¬ ¢itià  ¾n (Coombs, 2007). à  n  °nti-t °rniц¢h b °th iц¢ Ñ à  ¾mmà  ¾n  °ftà  µr dà  µÃƒâ€˜Ã¢â€š ¬Ãƒ  ¾Ãƒâ€˜Ã¢â‚¬ ¢itià  ¾n. Virtu °lly  °ll ц¢hà  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â‚¬ ¢ Ñâ‚ ¬urÑ h °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ  ° ц¢Ãƒ  µrià  µÃƒâ€˜Ã¢â‚¬ ¢ à  ¾f Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã¢â€š ¬rià  µt °ry Ñ hà  µmiц¢trià  µÃƒâ€˜Ã¢â‚¬ ¢ f rà  ¾m  ° ц¢inglà  µ và  µndà  ¾r th °t  °rà  µ uц¢Ãƒ  µd  °Ãƒâ€˜Ã¢â‚¬ ¢ thà  µ ingrà  µdià  µntц¢ fà  ¾r thà  µ ц¢Ãƒ  µvà  µr °l Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ b °thц¢ in thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ linà  µ. à  ¡là  µÃ‚ °ning. Thà  µ Ñ là  µÃ‚ °ning ц¢Ãƒ  µgmà  µnt bà  µginц¢ with  ° Ñ là  µÃ‚ °nà  µr-Ñ à  ¾nditià  ¾nà  µr dà  µÃƒâ€˜Ã¢â‚¬ ¢ignà  µd tà  ¾ rà  µmà  ¾và  µ à  ¾rg °niѠц¢  °nd Ñ à  ¾nditià  ¾n (in thiц¢ Ñ  °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ ц¢wà  µll) thà  µ hà  ¾là  µ b °rrà  µlц¢ fà  ¾r thà  µ ц¢ubц¢Ãƒ  µquà  µnt uÑâ‚ ¬t °kà  µ à  ¾f Ñ  °t °lyц¢t, fà  ¾llà  ¾wà  µd by  ° miÑ rà  ¾Ãƒ  µtÑ h ц¢tà  µÃƒâ€˜Ã¢â€š ¬. Thà  µ Ñ là  µÃ‚ °nà  µr-Ñ à  ¾nditià  ¾nà  µrц¢  °rà  µ tyÑâ‚ ¬iÑ  °lly Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã¢â€š ¬rià  µt °ry fà  ¾rmul °tià  ¾nц¢,  °nd mÃ à ‚ ¾Ãƒâ€˜Ã¢â‚¬ ¢tly Ñ à  ¾nц¢iц¢t à  ¾f Ñ à  ¾mmà  ¾n  °lk °linà  µ ц¢Ãƒ  ¾lutià  ¾nц¢. à  miÑ rà  ¾Ãƒ  µtÑ h ц¢tà  µÃƒâ€˜Ã¢â€š ¬ Ñ  °n bà  µ fà  ¾und à  ¾n thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ linà  µ, à  ¾xidà  µ linà  µ, Ñâ‚ ¬Ã‚ °ttà  µrn Ñâ‚ ¬l °tà  µ linà  µ  °nd with Ñ hà  µmiÑ  °l Ñ là  µÃ‚ °ning if th °t iц¢ thà  µ Ñ là  µÃ‚ °ning mà  µthà  ¾d uц¢Ãƒ  µd. Thrà  µÃƒ  µ Ñ hà  µmiц¢try  °ltà  µrn °tivà  µÃƒâ€˜Ã¢â‚¬ ¢  °rà  µ  °v °il °blà  µ. à †¦ulfuriÑ  °Ãƒâ€˜Ã‚ id-hydrà  ¾gà  µn Ñâ‚ ¬Ãƒ  µrà  ¾xidà  µ (Ñ à  ¾nц¢iц¢ting à  ¾f 5% ц¢ulfuriÑ  °Ãƒâ€˜Ã‚ id  °nd 1% tà  ¾ 3% Ñâ‚ ¬Ãƒ  µrà  ¾xidà  µ) iц¢ mà  ¾Ãƒâ€˜Ã¢â‚¬ ¢t Ñ à  ¾mmà  ¾n, fà  ¾llà  ¾wà  µd by ц¢ulfuriÑ  °Ãƒâ€˜Ã‚ id-Ñâ‚ ¬Ãƒ  ¾t °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ium (à  ¾r ц¢Ãƒ  ¾dium) Ñâ‚ ¬Ãƒ  µrц¢ulf °tà  µ (5% ц¢ulfuriÑ , 8 tà  ¾ 16 à  ¾unÑ à  µÃƒâ€˜Ã¢â‚¬ ¢/ g °llà  ¾n Ñâ‚ ¬Ãƒ  µrц¢ulf °tà  µ)  °nd  °mmà  ¾nium Ñâ‚ ¬Ãƒ  µrц¢ulf °tà  µ. In à  µÃ‚ °Ãƒâ€˜Ã‚ h Ñ  °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ, thà  µ miÑ rà  ¾Ãƒ  µtÑ h b °th iц¢ fà  ¾llà  ¾wà  µd by  ° ц¢ulfuriÑ  °Ãƒâ€˜Ã‚ id diÑâ‚ ¬, whiÑ h ц¢Ãƒ  µrvà  µÃƒâ€˜Ã¢â‚¬ ¢ tà  ¾ rà  µmà  ¾và  µ  °ny rà  µm °ining à  ¾xidizà  µr. à  bà  ¾ut 40 miÑ rà  ¾inÑ hà  µÃƒâ€˜Ã¢â‚¬ ¢ à  ¾f Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr  °rà  µ à  µtÑ hà  µd fà  ¾r thà  µ m °king hà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾nduÑ tivà  µ Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢. B °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µd à  ¾n  ° 3-4 à  ¾unÑ à  µ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñ  °rrying Ñ  °Ãƒâ€˜Ã¢â€š ¬Ã‚ °Ãƒâ€˜Ã‚ ity,  °Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬rà  ¾xim °tà  µly 0.0183 g °llà  ¾nц¢ à  ¾f miÑ rà  ¾Ãƒ  µtÑ h  °rà  µ uц¢Ãƒ  µd Ñâ‚ ¬Ãƒ  µr ц¢qu °rà  µ fà  ¾Ãƒ  ¾t à  ¾f Ñâ‚ ¬rà  ¾duÑ t run. Thiц¢ figurà  µ dà  ¾Ãƒ  µÃƒâ€˜Ã¢â‚¬ ¢ nà  ¾t inÑ ludà  µ  °ny ц¢Ãƒ  ¾lutià  ¾n th °t m °y bà  µ dr °ggà  µd à  ¾ut whà  µn thà  µ Ñâ‚ ¬Ã‚ °nà  µlц¢  °rà  µ mà  ¾và  µd tà  ¾ thà  µ nà  µxt t °nk. Thà  µ ц¢ulfuriÑ -Ñâ‚ ¬Ãƒ  µrà  ¾xidà  µ  °ltà  µrn °tivà  µ h °Ãƒâ€˜Ã¢â‚¬ ¢ ц¢Ãƒ  ¾mà  µ  °ttr °Ãƒâ€˜Ã‚ tivà  µ w °Ãƒâ€˜Ã¢â‚¬ ¢tà  µ trà  µÃ‚ °tmà  µnt  °nd Ñâ‚ ¬Ãƒ  µrfà  ¾rm °nÑ à  µ fà  µÃ‚ °turà  µÃƒâ€˜Ã¢â‚¬ ¢ (Coombs 2007): Gold was also used for electroless platting and the gold was used as nanoparticles with silica to make the silica surface conductive and that is depends on the chemical properties between the silica surface and the gold nanoparticles the connection between them depend on the charge for silver and the gold nanoparticles. In order to make the surface has conductivity and without using electroplating and that can be done in finding good organic linker to connect the gold with the silica and that will increase the reliability and increase the conductivity strong. The ultrasound irradiation has a good effect and it is useful to improve the joining of two material and to increase the dispersive properties and ultrasound can be used to increase the attachment to many kind of materials like silica and carbon glass and silver nanoparticles can be produced sonochemically and prepare it and deposited on the silica. The ultrasound has many of factors affecting on the distribution for gold nanopa rticles and these factors include the frequency and the temperature and irradiation time and the power and study these factors and the aim from that is to determine optimal dispersion condition for nanoparticles using ultrasound. The target copper electroplating this method is not only will increase the conductivity but will reduce the production cost . The electroplating for copper nanoparticles through hole metallisation is very important for the electrical industry such as printed circuit board (Coombs, 1988). à  n  °nti-t °rniц¢h b °th iц¢ Ñ à  ¾mmà  ¾n  °ftà  µr dà  µÃƒâ€˜Ã¢â€š ¬Ãƒ  ¾Ãƒâ€˜Ã¢â‚¬ ¢itià  ¾n. Virtu °lly  °ll ц¢hà  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â‚¬ ¢ Ñâ‚ ¬urÑ h °Ãƒâ€˜Ã¢â‚¬ ¢Ãƒ  µ  ° ц¢Ãƒ  µrià  µÃƒâ€˜Ã¢â‚¬ ¢ à  ¾f Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã¢â€š ¬rià  µt °ry Ñ hà  µmiц¢trià  µÃƒâ€˜Ã¢â‚¬ ¢ frà  ¾m  ° ц¢inglà  µ và  µndà  ¾r th °t  °rà  µ uц¢Ãƒ  µd  °Ãƒâ€˜Ã¢â‚¬ ¢ thà  µ ingrà  µdià  µntц¢ fà  ¾r thà  µ ц¢Ãƒ  µvà  µr °l Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ b °thц¢ in thà  µ à  µlà  µÃƒâ€˜Ã‚ trà  ¾là  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ Ñ à  ¾Ãƒâ€˜Ã¢â€š ¬Ãƒâ€˜Ã¢â€š ¬Ãƒ  µr Ñâ‚ ¬rà  ¾Ãƒâ€˜Ã‚ à  µÃƒâ€˜Ã¢â‚¬ ¢Ãƒâ€˜Ã¢â‚¬ ¢ linà  µ The metallization for PCB can be done by electroplating and electroless plating or electrolytic plating. Electroplating is using ionic metal which is supplied with electrons to make non-ionic coating on the materials a chemical solution is used in this process with electrical current supplier and this method is common for copper plating for electric circuits boards Electroless copper is using chemical material for plating and that occur without using electrical power gold, silver and gold is used in the electroless plating. This method was discovered in 1944 and this method involve the coating with metallic conductive material to the non-metallic material by using chemical materials without using electric power and that will reduce production cost. Electroplating was used for non-metallic material such as plastics (Epoxy) which are used in the printed circuits boards Dà  µÃƒâ€˜Ã¢â‚¬ ¢mà  µÃ‚ °r Desmear is the process which is used to remove smeared epoxy-resin and this process involves three steps (Solvent swell, Permanganate and nutulaizer) and that is important to ensure electrical conductivity for the layer after deposition process. Most electric Circuits boards material need removing to the drill smear and resin texturing prior to metallization. The solvent swell should be used before the permanganate and that increase the removing for drill traces and texturing. Solvent swell is used to prepare the material surface in etch step by using organic acid. Permanganate is used to remove the polymer from the surface and that will etch the surface. Neutulizer is using hydrogen peroxide with sulfuric acid to remove the smear left on the material surface after using permanganate and solvent swell. à  ¡hà  µmiц¢try à  ¾f Dà  µÃƒâ€˜Ã¢â‚¬ ¢mà  µÃ‚ °r à  l °ting Desmear process includs chemical reaction which are oxidation reactions by using alkaline permanganate ( Potassium or sodium) and this step called solvent swell. Alkaline permanganate is highly oxidizing medium. In the oxidation process for permanganate the permanganate reduced to manganate and manganate and then react with water to produce insoluble manganese dioxide in the reaction below: (Deckert, 1984) MnO4- + 2H2O + 3e- → MnO2 + 4OH- In the neutralization process includes removing the surface to ensure that all manganese dioxide are removed from the board surface and through holes. The manganese dioxide remnant from alkaline permanganate process can cause poor connection quality and poor hole wall adhesion problems. These problems can resolve by formation soluble manganese during the neutralization process.
Friday, January 17, 2020
The system of slavery and resulting
The system of slavery and resulting racial prejudice evoked negative reaction from many Americans. Their views came into conflict with the perception of slave labor as `normal` and economically sound part of everyday life prevalent in the mainstream community. some of them resorted to peaceful means for propaganda of their worldview like Harriet Beecher Stowe; others like Nat Turner initiated armed struggle to overthrow the hateful system.Nat Turner’s rebellion continues to evoke a mixed response, depending supposedly on the race of the evaluator and position on racial issues. On the one hand, Nat Turner was definitely a man of great leadership skills, able to motivate many people to fight against inhuman conditions of the Southern plantations.On the other, he is known to have ordered the murder of al white people including children and women, and the list of the rebellion’s casualties includes many people whose contribution to exploitation was but marginal.Similarly qu estionable are the methods of guerrilla warfare used by John Brown to liberate the slaves. This story demonstrates that centuries after, America continues to be divided on the issue of race and ways to overcome racial tensions.Harriet Beecher Stowe is certainly a less controversial figure. Her novel Uncle Tom’s Cabin is undoubtedly one of the most influential books in US history. Its significance was succinctly expressed by Abraham Lincoln in a personal meeting with the writer in 1862: â€Å"So you're the little woman who wrote the book that started this Great War!†[1]While the President’s words were surely a polite exaggeration, it is certain that Stowe’s novel helped wake up many citizens who, much like herself before 1850, remained passive onlookers of slaves’ sufferings, informed those remote from the issue, and helped shape and develop the Abolitionist Movement.However, in the South she received negative publicity as people began to accuse her of exaggerating the horrors of slavery. To this date, Americans still live to some extent in the shadow of these events. Still, debates continue as to the need to compensate descendants for the atrocities of slavery, methods to be used for the rehabilitation of the African American community, and heroes of the anti-slavery struggle.For centuries, women remained on the sidelines of American society. Slowly but gradually, their role continued to rise as women’s rights entered the political agenda of the United States as an important issue. This change was made possible by the efforts of many outstanding women who upheld the cause of female liberation through the toughest of times.Harriet Beecher Stowe can be considered a precursor of the Feminist movement. In a letter to George Eliot, Stowe insisted that â€Å"emancipation of slaves must be followed by the emancipation of women†[2]. In an attempt to combine the two, Stowe wrote in New York newspaper Independent that wom en can be active in the abolitionist cause, striving to leverage their influence by signing petitions, sharing information, and organizing community anti-slavery events[3].[1] Harriet Beecher Stowe Center. (2005). Harriet Beecher Stowe’s Life and Timeline. Retrieved June 10, 2006, from http://www.harrietbeecherstowecenter.org/life/[2] Cavendish, R. (2001). Publication of Uncle Tom's Cabin. History Today 51 (6), 54.[3] Harriet Beecher Stowe Center. (2005). Harriet Beecher Stowe’s Life and Timeline. Retrieved June 10, 2006, from http://www.harrietbeecherstowecenter.org/life/
Thursday, January 9, 2020
The Health Care System Operates Under Two Tier System
The Trinidad health care system operates under two tier system which consist of both public and private health care facilities, the main responsibility of the ministry of health is the overseeing of the health care sector, although this agency does not directly run the public health care facilities, the responsibility of this office is to set policies, goal and targets areas based on the assessment of the community health needs, as well as to allocate funds to the regional health authorities to finance the various health needs of the community. The public health the care system which includes four main hospital that helps to facilities the country medical needs, and can be access by the entire population of Trinidad and is offered free†¦show more content†¦In the case of serious medical emergency, a medical evacuation is needed to transport the individual to the closest health care facility that offers sufficient medical care, which may be located in another country, such as Miami in the United States. The private medical sector in Trinidad is very small comprising of four facilities which include: †¢ St Augustine private hospital †¢ Southern medical clinic †¢ West shore private medical hospital †¢ Adventist hospital These facilities are located either in Port of Spain, San Fernando and the West Mooring area, they are sufficient enough to treat most health problems but offer only a slightly better treatment than that of the public health care systems. Although the private sector is considered better than the public sector it is still incapable of handling serious illness and injuries especially those that require long term care. The health care system in Trinidad is not considered the best especially is seeking care at the public facilities according to article written by Akilah Holder who writes for the Trinidad guardian concerning the death of pregnant women who have had C- section at the hospital these are some of story. â€Å"Juliet Primus will never again hold her baby girl in her arms. She will not be around when baby Chasarah takes her first steps or says her first words. She will not be there to answer her questions when
Wednesday, January 1, 2020
Pasaporte Para Viajar a EEUU en Casos Doble CiudadanÃÂa
Frecuentemente, las personas con doble ciudadanà a se preguntan si pueden ingresar sin visa a Estados Unidos por turismo o negocios utilizando el pasaporte que es de un paà s incluido en el listado del Programa de Exencià ³n de Visas, aunque no residen habitualmente en dicho paà s. La respuesta es sà , aunque deben conocerse las excepciones y cuà ¡ndo pueden surgir los problemas. Ventajas e inconvenientes de viajar sin visa a Estados Unidos Los ciudadanos de 38 paà ses, entre los que se encuentran Chile y Espaà ±a, pueden ingresar a los Estados Unidos sin visa. Si llegan por avià ³n de là nea regular o barco deben antes de volar una autorizacià ³n que se conoce como ESTA. Una ventaja evidente de viajar sin visa es que la ESTA es mucho mà ¡s econà ³mica. En el momento de escribir este articulo el costo de la ESTA es de $14 frente a $160 de la visa B1/B2, cuyo precio final puede ser incluso superior para algunos paà ses, en aplicacià ³n de acuerdos de reciprocidad. Otra ventaja econà ³mica es que en caso de negacià ³n, se recuperan $10 en el caso de la ESTA, por lo cual el coste total es de $4. Por el contrario, si no es aprobada la solicitud de la visa de turista o negocios o la combinada de ambas, el solicitante no recupera nada. En otras palabras, pierde los $160 dà ³lares. Otro de los atractivos de viajar sin visa es que se evita tener que acudir a la entrevista en persona al consulado o Embajada, lo cual ahorra sin duda tiempo y en muchos casos tambià ©n nervios. En cuanto al tiempo, en la actualidad este problema es incluso mayor porque son numerosos los consulados en los que se necesita acudir con anterioridad a la entrevista a un Centro de Apoyo al Solicitante por el asunto de los datos biomà ©tricos, es decir, huellas digitales y fotografà a. Pero cuando se compara viajar con visa o sin visa, tambià ©n hay inconvenientes para este à ºltimo caso. Como regla general, si se ingresa a Estados Unidos con visa de turista se recibe una autorizacià ³n de 180 dà as, es decir, 6 meses. Ese plazo es el mà ¡s comà ºn, aunque puede ser inferior si asà lo decide un oficial de migracià ³n. El plazo autorizado està ¡ reflejado en el documento que se conoce como I-94. Por el contrario, si se viaja con visa el tiempo mà ¡ximo de estancia en Estados Unidos es de 90 dà as, ni uno mà ¡s. Otra gran diferencia es que si se ingresa con visa es posible solicitar una extensià ³n de la estancia y tambià ©n un cambio de visa, por ejemplo, de turista a estudiante. Sin embargo, si se ingresa a Estados Unidos sin visa no es posible alargar el plazo de 90 de ninguna de las maneras. En otras palabras, la ley no contempla la peticià ³n de extensià ³n o de cambio a otra visa no inmigrante. Es imposible. Por lo tanto hay que salir del paà s antes de cumplir los 90 dà as de presencia. Ademà ¡s, es recomendable evitar juegos como salir a Mà ©xico, Bahamas o Canadà ¡ y regresar con la idea de obtener asà otros 90 dà as. Lo cierto es que en estos casos se regresa no con un nuevo plazo, sino con los dà as que quedasen del anterior. Incluso hay que tener en cuenta que se està ¡ jugando con fuego en los casos de salida al paà s de origen o cuando se viaja a paà ses adyacentes como Mà ©xico y Canadà ¡ y se fuerza al là mite el plazo de los 90 dà as antes de salir de tal manera que ya no hay dà as restantes en el primer plazo cuando se regresa y se quiere obtener un nuevo trimestre. Puede suceder que el oficial de migracià ³n considere que se està ¡ viviendo en Estados Unidos, sospeche que se està ¡ trabajando o estudiando sin visa, etc. lo cual llevarà a a que se prohà ba el ingreso al paà s e incluso acabar con el castigo de una expulsià ³n inmediata.  ¿Viajar con un pasaporte o con los dos? Esta es una pregunta muy comà ºn entre las personas con doble ciudadanà a que deciden ingresar a Estados Unidos sin visa. La respuesta no es à ºnica y se ilustra mejor con casos especificos. Por ejemplo, en el caso de un argentino que vive en Argentina pero que tiene tambià ©n pasaporte italiano deberà a viajar con sus dos pasaportes. Asà , saldrà a de Argentina con el de ese paà s pero mostrarà a ya allà el italiano para que le permitan embarcar. Al ingresar y tambià ©n al salir de Estados Unidos. Al llegar a Argentina, mostrarà a ese pasaporte para entrar a su paà s. Otro ejemplo distinto es el de, por ejemplo, un argentino que reside habitualmente en Italia y tiene tambià ©n pasaporte de ese paà s. En este caso, utilizarà a solamente el pasaporte italiano. Quà © problemas pueden surgir al llegar al control migratorio de los Estados Unidos En principio, los problemas potenciales son los mismos si se viajan con visa o sin visa. Ninguna de las dos situaciones garantiza el ingreso. Lo que importa es que la persona que quiere ingresar como turista tiene que ser considerada como elegible y admisible para ingresar a Estados Unidos. Si se considera que reà ºne tal cualidad, no hay problema. De hecho, son miles las personas con doble ciudadanà a que deciden viajar sin visa y nunca han tenido problemas. En otras palabras, el problema no es la visa o la no visa, sino si se cumplen los requisitos para ingresar o no. En este punto decir que hay noticias que apuntan a que se les ha negado el ingreso en repetidas ocasiones a dominicanos que viajan a Estados Unidos recià ©n adquieren la ciudadanà a de un paà s incluido en el listado de los Paà ses con Exencià ³n de Visado (VWP, por sus siglas en inglà ©s). No es que no puedan viajar, es que por la razà ³n que sea puede haber levantado sospechas de que su intencià ³n es quedarse en los Estados Unidos. Si se tiene duda, la opcià ³n es olvidarse de viajar sin visa y solicitar una B1/B2. Finalmente decir en relacià ³n a este punto de los posibles problemas que pueden encontrar los cubanos para embarcar sin visa en un vuelo hacia Estados Unidos. Lo cierto es que miles de cubanos embarcan e ingresan sin ningà ºn problema. Pero no es menos cierto que se les puede impedir incluso embarcar si se sospecha que su intencià ³n es quedarse en Estados Unidos y pedir que se les aplique la Ley de Ajuste Cubano una vez que està ¡n allà . Excepciones a viajar sin visa en los casos de doble ciudadanà a En determinadas ocasiones no es posible que las personas con doble ciudadanà a decidan que prefieren viajar sin visa y deben solicitar la visa si es que quieren viajar como turistas a los Estados Unidos. Entre otras situaciones destacan las siguientes: Cuando previamente le han negado una visa, aunque la solicitaran con otro pasaporte. La visa se le negà ³ a la persona, no al pasaporte y las autoridades migratorias saben que se trata de la misma persona al cotejar las huellas digitales que se dieron al solicitar la visa con las que se toman en el punto de ingreso a Estados Unidos (puerto, aeropuerto o paso terrestre fronterizo). Otra situacià ³n que pide por solicitar la visa es cuando previamente una persona ha tenido una visa americana y à ©sta ha sido cancelada. Otro caso es cuando se ha visitado anteriormente Estados Unidos y el visitante se ha quedado mà ¡s tiempo del autorizado. Finalmente, todos los casos en los que ha habido en el pasado situaciones problemà ¡ticas, como violaciones migratorias, deportaciones, expulsiones inmediatas, etc. Otras situaciones de doble ciudadanà a o nacionalidad Estados Unidos, por regla general, no tiene ningà ºn problema con la doble ciudadanà a, tambià ©n conocida como doble nacionalidad. Esto es asà en el caso de extranjeros que pueden utilizar el pasaporte que deseen, como se ha explicado en este artà culo, pero tambià ©n en otros como para aplicar por visas limitadas a ciertos paà ses como es el caso de la visa de inversià ³n E-2. Asà ,por ejemplo, un venezolano no puede beneficiarse de esa visa pero si cuenta con otro pasaporte como puede ser el de Colombia, Espaà ±a, Portugal, etc, puede solicitarla. Pero tambià ©n es el caso de sus propios ciudadanos. Estados Unidos admite la doble nacionalidad y casi no impone là mites a esta situacià ³n. De interà ©s para turistas en Estados Unidos La mejor forma de evitar problemas migratorios, tanto si se ingresa con visa o con ESTA, es cumplir con la ley, por lo que se recomienda tomar este test para conocer aspectos fundamentales. El caso especial de Canadà ¡ Como regla general, los ciudadanos de Canadà ¡ no necesitan ni visa ni ESTA para ingresar a Estados Unidos como turistas y el permiso de estancia es por 6 meses. Esto aplica a los canadienses que tambià ©n son ciudadanos de otro paà s, es decir, a los casos de doble ciudadanà a. Sin embargo, no aplica a los extranjeros que tienen residencia en Canadà ¡. Este es un artà culo informativo. No es asesorà a legal.
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