PCB_MF

3) Pad Diameter for double sided PCB’s In PCB‟s with PTH, the width of the Annul ring should be at least 0.5mm but preferably more. A solder pad diameter is approximately 2.5 to 3 times of the drilled hole diameter. The conductor width should always be less than the solder pad diameter, but preferably about one third Pad dia = Hole dia + 2 (width of Annular ring) Example: For: 1.0mm lead dia (3 times) 3.0mm = 1.3mm + 2(0.85) (2.5 times) 2.5mm = 1.3mm + 2(0.6) Mis – Registration of drilled hole is known as OFFSET tolerance of manual eye sight is 0.1 to 0.25mm For 0.5mm lead dia (3 times) 1.5mm = 0.8mm + 2(0.35) In this case the width of annular ring is less than 0.5mm Remedy: 0.8mm + 2(0.5) = 1.8mmNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page51

UNIT:5 BOARD CLEANING BEFORE PATTERN TRANSFER 5.1 Pattern transfer In this process the generation of the pattern from artwork or Photographic film on to a copper or other metal clad laminate. This method known as Print and etch method or the etched foil process. The fabrications of PCB, There are two methods to transfer the pattern from the Photographic film to the laminate. 1. Photo printing process 2. Screen printing process Before going to transfer the pattern on to the laminate, it should be free from oil, dust, grease, the finger print and foreign particles. 5.2 Organic soils Possible sources causing contamination could be the equipment used for shearing, drilling, punching. The air from the air compressor or contaminated cleaning solutions for such equipment. It can be degreased with a suitable solution or solvent. In normal handling of laminates, will leave finger prints and sweat marks. These marks are usually quite difficult to remove because of their corrosive nature. Only Scrubbing or Etching can help here. 5.3 Metallic soil: Metallic soils are mainly oxides and corrosion products on the copper surface which are caused by atmospheric attack and residuals remains after poor rinsing and drying. In particular, the Sulphur compounds found in the air of an industrial environment can form metallic soils which are not easy to remove. Therefore Etching and Scrubbing with abrasives has to be employed. 5.4 Particulate matters Under particulate matters, we group the particles from PCB machining and the remnants [Small remaining quantity] from the abrasive cleaning whichNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page52

get embedded in to copper surface. Water rinsing and the blowing with compressed air usually remove only the loose particle. Hence for the thorough cleaning of particulate matters, wet brushing is recommended. 5.5 Vapour degreasing Laminate copper surface is vapour degreased and removes the oil and soil (such as oxides, hydroxides and salts) contaminates from the surface. Two of the most commonly used solvents for vapour degreasing or trichloroethylene and perchloroethylene 5.6 Mechanical cleaning Mechanical cleaning operation being with sanding when the boards have been drill or with abrasive scrubbing process only on wet condition. So during wet sanding with 280-600 grit water resistant abrasive paper is used and scrubbing abrasive fiber roller are used and some other machines use brushes and slurry of pumice. The out coming boards is cleaned and dried with steam heater or hot blow air. 5.7 Chemical cleaning Concentrated alkali chemicals are used to remove the oil or grease particles on the surface of laminate. The concentration are between 80-100% at a temperature between 60-75°c for 20-30min. Rinsing after alkaline cleaning is effectively carried out by using filtered (oil and solid free) tap water, water immersion, followed by a strong spray. Ensures complete removal of cleaners, neutral or acidic cleaners are sometimes used for reason of attack of hot alkaline solution on exposed epoxy or polyimide substrate.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page53

UNIT 6 PHOTO PRINTING PHOTO PRINTING In this process coating of photo resist (liquid or dryfilm) on the laminate surface which can be divided into two groups according to their applications 6.1 Liquid photo resist Liquid photo resist are organic liquids which when expose to light of the proper wavelength are chemically changed the solubility of certain solvent (developers).There are two types: 1) Negative Acting 2) Positive Acting 1. Negative Acting: It is initially solvable (before exposing) in the developer, but after exposing it becomes polymerized and insoluble in developer. 2. Positive Acting: It is opposite to Negative acting. It is initially not solvable in developer, but after exposing initially not soluble in developer, but after exposing polymerized position become soluble in developers. 6.2 Negative Acting Dry film Resist It is first soluble in its developers and after exposing it becomes polymerized, and not dissolved in developer. Normally dry film photo resists from 12.5µ to 75 µm. thickness are available, and the photopolymer is sand witched between a layer of polyester film on one side and a polypropylene or polyethylene sheet on the other side. PROCESSING: Cleaning: a) Degreasing in Trichloroethylene vapour b) Abrasive cleaner scrub (pumice)NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page54

c) Thorough cleaner rinse (No residue) d) Blow dry with clean air e) Oven dry 50-60oc, 10-15mins Surface coating: Spray or dip coating (Liquid photoresist) or laminate using heat and pressure (dry film photoresist) through machine. If it is dry film resist, during this process the polyethylene/polypropylene coversheet is removed. 3) Prebaking and normalizing: Liquid photoresist after coating immediately oven dry at 45oC to 75oc in air circulating type oven which is well ventilated for 15 to 20 mins. is called prebaking. Dry film photoresist after lamination immediately cooled between 10-15min for better dimensional stability called normalizing period. 6.3 Exposing Exposure is carried out by registration of the photographic film (emulsion side) onto the polyester sheet, the two are then placed in a vacuum frame for intimate contact between surfaces. The proper exposing time will depend upon the light intensity, Temperature, photopolymer type, thickness and type of equipment being used. 6.4 Developing Developing after stabilization (1-15 mins) starts with the peeling of the protective polyester cover sheet. The developing solution depends upon the photoresist used. Post Baking: Baking after developing at temperature between 40oC and 60oC for 10 mins. Acids pattern plating adhesion to a considerable extent. The chemical resistance is enhanced by baking. Etching:NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page55

After post baking the circuit going to mild etching. Etching can be done using ammonium persulphate or other common Acid mixtures 6.5 Rinsing Thorough rinsing and in some cases scrubbing and rinsing is needed. 6.6 Drying Blow dry with filtered Air. 6.7 Plating Most printed circuits, acid plating solutions are used. Resist Removal: This is exceedingly rapid worth variety of organic solvents or strong Alkalis 60oC – 75oC are effective) are used. 6.8 Single sided pcb fabrication by print and etch processNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page56

6.8 Single sided PCB fabrication by plate and etch processNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page57

UNIT 7 PLATING, ELECTRO PLATING, PTH 7.1 Electroless Copper Plating Process In PCB fabrication process the base material is copper clad laminate. So copper being the conductive material on the PCB and forming the conducting track patterns. It is able to tarnish if exposed to atmosphere over long period of time. So it should be protected from the tarnishing and improve the solderability. There are two methods one is applying lacquer and other is non-tarnishing metals coating like tin. Tin and lead alloy coating silver, nickel and gold plating. For long term storage properties of the lacquer variation in thickness composition and curing cycles this causing unpredictable deviation is soldering. Plating a solderable metal over the copper tracks has hence become a standard practice to afford solderable protection to the copper tracks. Through hole plating it has become it provides side to side connection with high reliability at a relatively low cost for the subsequent of components. If there are edge connectors in the PCB‟s such connectors are required to possess a high degree of wear resistance and a very low contact resistance. This trigged off intensive research in precious metal plating. The most commonly used material being gold. PLATING TECHNIQUES. Plating of a metal can be accomplished on a copper by three methods. They are a) Immersion Plating b) Electroless Plating c) Electro plating 7.2 Immersion Plating It is the deposition of metallic coating on the substrate by chemical replacement, from a solution of a salt of the coating metal. The substrateNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page58

metal reduces the atoms from their ionic state in the solution.Eg. Tin immersion plating, copper is normally more noble (less readily reactive) than tin and thus it would not be expected that the reaction. Cu + Sn2 = Sn +Cu2 would take place Simultaneously Sn2 and Cu2 metal ions positively charged due to the lack of two electrons. However the electrode potential of copper can be made much +ve by the in co-operation of Complexing agent for copper in the tinning solution. Complexing agent for copper in the tinning solution Complexing agent thiourea form stable complex with copper and is an ingredient of some other solutions. 7.3 Electroless plating This mechanism is similar to electroplating but the source of electrons is a chemical reduction agent. In electroplating electrons are obtained from a DC power source to reduce metal ions to the metallic state in electroless plating no current is used in the deposition. With the advantage of the PTH technology it has become necessary to provide a copper layer once drilled hole on its insulting area to obtain electrical conductivity subsequent electrolytic copper deposition. Mechanism: In electro less plating copper is reduced from its ionic state in solution by means of chemical reducing agent rather than by electric current. The reducing agent reduces the metal ions in the solution to metal atoms for deposition. The process produces a continuous buildup of metal coating on a suitable substrate by simple immersion in an appropriate aqueous solution. A chemical reducing agent in the solution supplies electrons from the reaction. Mn⁺+ne----Mo. but the reaction takes place only on a catalytic surface. A catalytic surface on which a noble metal like palladium is seeded to trigger the chemical reduction process.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page59

7.4 Activator• Strong acid or strong alkalis.• Mixed catalyst solution :• Stannous solution dehydrate --- 50-60gm/ltr•• Palladium chloride ---0.25-1.0gm/ltr• Hcl ----- 200-300ml/ltrBoth sensitizer plus activator and the mixed catalyst produced a catalyticfilm of palladium. However whereas the first method produce the film overthe entire panel, the second one produces it only on the surface of the resin,the copper foil of the laminate remains uncoated. The thin palladium maycompromise adhesion between the base copper and the plated copper.The sensitizing step involves immersion of the panel in an acetic solution(sensitizer) containing stannous ions which are absorbed on the surface ofthe resin. The stannous ions are reduced, the palladium ions and thestannous which oxidized to stannic ions according to a redox reaction.7.5 Electroless Bath1. Electroless Bath: CuS042. A chelating or complexing agent : Rochelle salt, sodium potassiumtartrate or EDTA, other tartrate triethanol amino and diethyl amino3. A reducing agent: Formaldehyde.4. Strong alkali – NaOH or KOH5. Stabilizer : potassium cyanide or organic compounds of either sulphuror sodium. Eg: Two mercapto – bonzothizole or benzyl – seleno Acetic acid.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page60

Cupric ions reduces metallic cu + acetic acid. PTH Process Electroless copper plating process steps: 1) Alkali cleaning 2) Rinse 3) Mild Etching 4) Rinse 5) 10% H2So4 6) Rinse 7) HCL 8) Activator 9) Rinse 10) Post Activator 11) Rinse 12) Electro less copper plating 7.6 Types of Electroplating It‟s the process of depositing an adherent metallic coating upon a negatively charged electrode the medium is water in which metal salts have been dissolved as a current source of metallic ions. It‟s the purpose of electroplating to obtain a metallic coating that has different properties or dimensions than those of the basic metal. As applied to PTH the negatively charged electrode in the PCB as follows: 1) Hole wall build up. 2) Conductivity 3) Wearability 4) Low constant resistant 5) Solderability To accomplish the foregoing many different plating process are :NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page61

1) Copper electroplating 2) Tin plating 3) Nickel plating 4) Gold plating 7.7 Copper plating Copper has met with wide acceptance as the base conductor metal in PCB‟s fabrication. It has excellent electrical conductivity, is readily plated is low cost and give highly reliable result. Copper is readily activated and hence a good metal bond is obtained between copper and other plated metals In PTH plating the thickness should not be less than 25µm, can carry 10A, through 1mm hole. Acid copper plating is widely used in PCB‟s plating. 7.8 Tin Plating Here tin is the most commonly used plated finish for printed circuits. The advantages are good solderability and easily control the process. 7.9 Gold Plating Gold being by nature soft, is always rated alloyed with minimum quantities of Indium, cobalt or nickel to provide the desired hardness.Gold is plated on edge connector tabs to provide 1) Low contact resistance 2) High wear resistance its customary to plate 5µm gold over copper or 2.3µm, gold over a nickel under coat of 4µm. 7.10 Nickel Plating Nickel is the most often used as a undercoat for gold to act as a barrier over to copper migration as well as increase the wear resistance of the coating thereby reducing the minimum gold deposit needed for a given applicationNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page62

UNIT – 8 ETCHING In all subtractive PCB process the final copper pattern is formed by selective removal of the unwanted copper, which is not protected by an etch resist. The technical, economical and environmental needs for the practical application of process control have brought about major improvement in etching techniques. Batch type operation with their variable etching rates and long down times have been replaced with continuous, constant etch rate process. Acidic etchants with their generally lower dissolved copper capacities are being replaced by alkaline process with high copper dissolving capacities and potential for regeneration. 8.1. Etchants Solutions 1. Alkaline Ammonia Etching 2. Cupric Chloride Etching 3. Ammonium Persulphate Etching 4. Ferric Chloride Etching 5. Chromic Acid Etching 8.2 Equipment and Techniques Etching techniques and the equipment used today have evolved four basic methods. 1. Immersion Etching 2. Bubble Etching 3. Splash Etching 4. Spray Etching 8.3 Types of etching IMMERSION ETCHING: In this techniques deep tank is used to immersion the pieces. The PCB is immersed in the solution until etching is complete, and it requires longNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page63

process time, and intolerable factor in large quantity production. Heating the etch solution and agitation of some form speed up the action. This method is suitable for laboratory etching of small or prototype boards. BUBBLE ETCHING: Bubble etching is a modified form of immersion etching. Air is bubbled through the solution and past the work being etched. Air passing through the solution has two functions. It ensures the availability of fresh etchant at the surface and rinse away dissolved metal. It provides oxygen which increases the additional oxidizing power and regenerating the etchant. Air pressure up to 2psi is used. EX:- Ammonium persulphate & chromic Acid etchant. SPLASH ETCHING: Splash etching offers distinct advantages over bubble etching with regard to evenness of etch and minimization of undercut. But few pieces only etch at aNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page64

time; even when double paddles are used. A large volume reservoir is built in to the bottom of the tank to minimize solution replacement. The etch solution is picked up in a cup attached to a motor driven shaft and thrown by centrifugal force towards the boards being etch. Speed of shaft rotation and cup design determine the amount and force of solution coming in contact with the board. SPRAY ETCHING: Spray etching is the most common method since it is fast well suited to high production and capable of very fine line definition. Spray etching techniques include the single and double sided etching with either horizontal or vertical positioning of the work. In spray etching, the etchants is pumped under pressure from the pump via pipe networks to the nozzles and from there gets splashed on to the boards.Spray etching machines can offer very high etching uniformity and to a fast etching rate. The high etching uniformity is achieved by spraying through a full number of equally distributed nozzles in ring supply. A high etching rate is the result of the continuous flow of fresh etchant over the board and the air oxygen absorbed in the etchant through spraying. From the designing point of view, spray etching machine can be classified into the laboratory type and conveyorised etching machines.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page65

8.4 Ferric chloride etchant Ferric chloride etchant is used in small scale PCB production. In high volumeproduction ferric chloride is not much importance because it can hardly beregeneration and it attacks the common metal etch resists.[Tin &Tin Lead].OPERATION:Ferric chloride - 450 g/lSpecific gravity - 1.3-1.4 kg/dmHCL - 10% of the etchant volumeTemperature - 20-40˚c.NOTE: 5.1kg of ferrite chloride dissolves 1kg of copper.8.5 Cupric chloride etchantCupric chloride can replace ferric chloride in large scale etching print & etchtype boards. Cupric chloride can be easily regeneratability, easily disposaland higher copper dissolving capacity (up to 150 gm/ltr) and no sludgeformation. OPERATION:NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page66

Cupric chloride - 200g/l orCopper concentration - 40g/l(for initial etchant)Water - 770mlHydrochloric acid - 200ml/ltrHydrogen peroxide - 30ml/ltrTemperature - 30˚-40˚C8.6 Chromic acid etchantChromic acid etching is usually carried out with addition of Sulpuric acid,hence it is also called chromic Sulpuric acid etching. It is widely usedbecause of its higher corrosiveness which works well with all kind of metalresist, and fast etching rate with little under etching. Chromic acid etchant ishighly toxic, heavy pollution and health hazard, so it is not recommended.OPERATION:CrO3 Chromic acid - 240g/lH2SO4 Sulpuric acid - 60ml/lNa2so4 Sodium sulphate - 40g/lTemperature - 20˚-30˚c8.7 Alkaline ammonia etchant Alkaline etching with the ammonium hydroxide complexion has foundincreased acceptancy owing to continuous operation; compatibility with mostmetallic and organic resist and especially solder, minimum under cut, highcapacity for dissolved copper and fast etch rate. In continuous (closed loop)operation provides constant etch rate, high work output, ease of control andreplenishment and improved pollution control.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page67

UNIT-9 MECHANICAL MACHINING OPERATIONS 9.1 Introduction Laminate machining consists of the mechanical processes by which circuit boards are prepared for the vital chemical processes of Image Transfer, Plating and Etching. Such processes as cutting to size, drilling holes and shaping have major effects on the final quality of the printed board. This chapter will discuss the basic mechanical processes which are essential to producing the finished board. 9.2 Punching holes (piercing) It is possible to pierce holes to the paper phenolic FR2 and paper Epoxy FR3 material. By using the punch and Die, Holes can be pierced. Always pierce with the copper side up. They are for use where inspection standards permit rough-Quality holes. 9.3 Blanking When parts are designed to have shapes other than rectangular and the volume is great enough to justify the expense of Building a die, the parts are frequently punched from sheets by using Blanking die. A Blanking operation is well adapted to paper-based material. Odd shapes that cannot be feasibly produced by shearing or sawing are either Blanked or Routed. 9.4 Shearing When copper clad laminate are to be sheared, the shear should be set with only 0.025 to 0.05mm clearance between the square 9.5 Sawing Sawing the copper clad laminates is best accomplished with a circular saw, which gives a smoother cut and because of the abrasive nature of laminated materials, diamond-steel-bonded saws can be used.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page68

9.6 Routing Routing offers the fabricator the advantages of superior edge finishes and closer tolerances than can be obtained from shearing or sawing. It can eliminate the expense of blanking dies and the long lead times associated with hard tooling. Now, when coupled with the use of multiple-spindle machines, the labor costs of routing can be competitive with those of die blanking. When a design has traces close to the board Edge, Routing may be the only blanking method that will produce acceptable boards. 9.7 Drilling 1. To produce an opening through the board, this will permit a subsequent process to form an electrical connection between Top, Bottom and sometimes in Intermediate conductor path ways. 2. To permit through the board component mounting with structural integrity and precision of location 9.8 CNC / laser drilling Holes or via‟s through a PCB are typically drilled with tiny drill bits made of solid tungsten carbide. The drilling is performed by automated drilling machines with placement controlled by drill file. These computer generated files are also called numerically controlled drill (NC) files or „Exelon Files”. The drill file describe the location and size of each drilled hole. When very small vias are required, drilling with mechanical bits is costly because of high rates of wear and breakage. In this case, the Vias may be evaporated by „Lasers‟. Laser drilled vias typically have an inferior surface finish inside the holes. These holes are called “Micro vias.It is also possible with controlled depth drilling laser drilling or by predrilling the individual sheets of PCB before lamination to produce holes that connect only some of the copper layers, rather than passing through the entire board. These holes are called “Blind vias” when they connect an internal copper layer to an outer layer, orNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page69

„buried vias‟ when they connected two or more copper layers. The walls of the holes, for boards with 2 or more layers, are plated with copper to form plated through holes that electrically connect the conducting layers of the PCB. For multilayer boards with 4 layers or more drilling produces a smear comprised of the bonding agents in the laminate system before the holes can be plated through the smear must be removed by chemical de-smart process or by “Plasma etch”. 9.9 Laser & system concept LASER : Light amplification via stimulated Emission of radiation. The most commonly used industrial machining lasers are 1) NDYAG laser (Neodymium drifted yittrium Aluminum garnet) 2) Co2- carbon dioxide laser, which has a gaseous lasing medium. 3) They are versatile in terms of applications and capable of the output required to weld, braze, solder, cut & mark. 4) Laser can drill 6,000-25,000 holes/min UV/YAG laser can drill 20-30µm hole. CO2 laser can drill 50µm holes. DRILLS: Drills for making Holes in printed Circuit Boards are usually made of Tungsten Carbide. This is due to interrelated needs of cost, wear properties, machinability and handling properties. No other material has proved to be as suitable.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page70

UNIT 10 MULTI LAYERED PCB – Important concepts 10.1 Description Multilayer boards consists of a certain number of thin PCB‟s stacked together and adhesively joined with insulting Prepregs to form one rigid board. Electrical connection between the different conductive layers is done with plated through holes. Multilayer printed wiring emerged as a solution to the problem of interconnecting miniature electronic components into complex systems. 10.2 Need for multilayer The condition which will necessitate the use of multilayer printed wiring generally are the following. : 1. When weight and volume saving in interconnection are the parameters importance as in military airborne, missile and space applications or when integrated circuits are utilized. Multiplanner conductor structure a reduction in weight and volume of the interconnection proportionate with the size and weight of the components it interconnected. The exact amount of space and weight savings is determined by the packaging design. 2. When the complexity of interconnection in sub systems will require very complicated and costly wiring or harnessing. 3. When coupling or shielding of a large percent of interconnections is required. The high capacitance distributed between the different layers gives a good decoupling of power supply and this permits high speed circuits. 4. When frequency requirement call for careful control and uniformity of conductor (wave impedances with minimum distortion in signal propagation) characteristics from board to board is high importance.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page71

5. When the spacing of terminal points does not allow a sufficient density of interconnection on two sided circuit boards. 6. The layout design is greatly simplified on account of the absence of the VCC & ground lines on signal planes. Multilayer Board trends • Finer Lines • Increased Density • Smaller holes • Closely spaced holes • Larger boards • Higher speeds • Surface mount • Higher power dissipation. MLB advantages : • Low-loss and low-dielectric constant materials as speeds become faster. • Dimensional stability as features become smaller and board bigger. • Improved thermal properties as power becomes adhesion. • Surface mounted components become more common. • Lower x-axis expansion as board thickness increases. Multilayer Board Types: • Conventional plated through hole. • Buried via • Blind via 10.3 Buried Via • A buried via can be describe as a plated through hole connecting two or more layers of multilayer board, buried inside the board structure but not coming to the external surface of the board. • Note in this example that two via holes can be stacked up over one another in x-y direction, whereas in a conventional multilayer only one could be used in this location. • The buried via construction is therefore used when signal trace routing is very dense requiring more via sites connecting signal.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page72

Layers and more channels for signal traces than a conventional multilayer can offer. • When smaller holes are used, smaller pads can be used which then allows even more room for signal lines. 10.4 Blind via • The blind via is a plated through hole connecting the surface layer to one or more layers of a multilayer board which does not go through the entire board thicknessNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page73

• These holes can be used on both sides of a multilayer board and canbe used in conjunction with via and component holes which go throughthe board.10.5 Core layerThe multilayer build up process starts with a set of raw two-sided laminatelayers coated with copper on each side surface destined to become innerlayers are etched in this form. Surface destined to become outer layers areleft fully copper-plated. These etched laminates are called cores. Thethickness between opposing layers on a core depends on the thickness ofthe original laminate.10.6 Board lay upThe layering of a multilayer board should be kept symmetrical and it is bestto have an EVEN number of copper layers. These requirements will help themanufacturer to keep the finished board flat. Constructions which areasymmetrical are more prone to warp, which subsequently causes manyproblems in board assembly soldering and testing as well as in the systemcabinet. A particular multilayer board can be made from laminate clad withcopper on one or two sides‟ base laminate, copper foil and Prepreg and inmany different combinations10.7 ConstructionFor example: 1.6mm, 4 layer board constructionCopper layer, electrolytic - 25µmCopper layer base no. 1 - 35 µmBase laminate - 640 µmCopper layer base no. . - 35 µmPrepreg - 120 µmCopper layer base no. 3 - 35 µmBase laminate - 640 µmCopper layer base no. 4 - 35 µmCopper layer, electrolytic - 25 µmNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page74

- 1590 µm1590 µm = 1.59mmNote: 10% tolerance is acceptable10.8 Multilayer PressTo laminate the multilayer board a 25 ton press is required, the pressureneeded to make laminates with void-free intermediate expose layers is inthe range of 200 to 500 psi. The pressure is applied to drive the air bubblesout from the B-Stage resin towards the edges of the board].As some airbubbles get trapped in the edges by the time curing starts, a border ofperhaps 25mm on each side should be left for trimming. The temperatureneeded for laminating of epoxy is typically 180oc. The press must be capableof maintaining an even temperature over the entire laminate area.10.9 Multilayer laminating process 1. The inner layers are formed by print and etch process and tooling hole to be drilled. 2. Dielectric thickness for these inner layers will depend upon the number of layers and over all board thickness specification. 3. Inner layers must be treated with a black oxide coating solution. 4. Keep the Prepreg and copper foil to the top and bottom of pre-etched two sided inner layer panels. 5. The platens and the press plates are pre heated to a temperature of 180oc 6. The multilayer package assembly is placed between the plates, as shown in the figure. 7. Press with 150-350PSI pressure. During this process, the prepreg, resin liquefies for a few minutes, flows to fill voids and spaces in theNTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page75

etched circuitry, replaces the air and finally cures to bond the layers together. 8. After the stack is cooled to near room temperature in the press, MLB‟s are carefully removed. After trimming proceed the remaining process like double sided PCB fabrications.NTTF_DIPLOMA IN ELECTRONICS_SEM3_PCB DESIGN AND FABRICATION_REV7_JUNE 2017 Page76

Qpf REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION (NEC, RNTC, JNTC, TNTC) DIPLOMA IN ELECTRONICS - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 Di electric constant of an Air is________1.2 _______ file is required to drive the Photo plotter1.3 The required thickness of the PTH is ________1.4 PCB’s are fabricated by_______ process.1.5 Di electric strength of Glass epoxy material is ________2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 The computer generated NC drill files are needed for_______ drilling. () ()a) CNC b) Opticals c) LASER d) Plasma () ()2.2 The thorough cleaning of particulate matters can be done by _______ processa) washing b) drying c) wet brushing d) wiping2.3 Remote and calculator key tabs to be plated with _______a) Silver b) Nickel c) Zinc d) Gold2.4 ____ is the CAM software to view the gerber files..a) Camtastic b) Proload c) Orcad d) Proteus2.5 When PCB layer count increases, the ratio of the risk factors will be ______a) Less b) more c) Nil d) Nominal3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 B stage a. Inner layer3.2 decoupling capacitor b. Black oxide3.3 Metallic soil c. electroless plating3.4 PTH d. Prepreg3.5 Multilayer e. scrubbing f. Ceramic

Qeӛ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION (NEC, RNTC, JNTC, TNTC) DIPLOMA IN ELECTRONICS - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 Di electric strength of Glass epoxy material is ________1.2 PCB’s are fabricated by_______ process.1.3 The required thickness of the PTH is ________1.4 _______ file is required to drive the Photo plotter1.5 Di electric constant of an Air is________2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 When PCB layer count increases, the ratio of the risk factors will be ______ () ()a) Less b) more c) Nil d) Nominal () ()2.2 ____ is the CAM software to view the gerber files.. a) Camtastic b) Proload c) Orcad d) Proteus2.3 Remote and calculator key tabs to be plated with _______ a) Silver b) Nickel c) Zinc d) Gold2.4 The thorough cleaning of particulate matters can be done by _______ processa) washing b) drying c) wet brushing d) wiping2.5 The computer generated NC drill files are needed for_______ drilling.a) CNC b) Opticals c) LASER d) Plasma3.0 MATCH THE FOLLOWING 1X5=5 AB3.1 Multilayer a. electroless plating3.2 PTH b. Inner layer3.3 Metallic soil c. Black oxide3.4 decoupling capacitor d. Prepreg3.5 B stage e. scrubbing f. Ceramic

QeӮ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION (NEC, RNTC, JNTC, TNTC) DIPLOMA IN ELECTRONICS - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 PCB’s are fabricated by_______ process.1.2 _______ file is required to drive the Photo plotter1.3 Di electric strength of Glass epoxy material is ________1.4 The required thickness of the PTH is ________1.5 Di electric constant of an Air is________2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 ____ is the CAM software to view the gerber files.. () ()a) Camtastic b) Proload c) Orcad d) Proteus () ()2.2 The thorough cleaning of particulate matters can be done by _______ processa) washing b) drying c) wet brushing d) wiping2.3 When PCB layer count increases, the ratio of the risk factors will be ______a) Less b) more c) Nil d) Nominal2.4 Remote and calculator key tabs to be plated with _______a) Silver b) Nickel c) Zinc d) Gold2.5 The computer generated NC drill files are needed for_______ drilling.a) CNC b) Opticals c) LASER d) Plasma3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 B stage a. Black oxide3.2 decoupling capacitor b. electroless plating3.3 Metallic soil c. scrubbing3.4 PTH d. Inner layer3.5 Multilayer e. Prepreg f. Ceramic

Qe฿ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION (NEC, RNTC, JNTC, TNTC) DIPLOMA IN ELECTRONICS - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 _______ file is required to drive the Photo plotter1.2 The required thickness of the PTH is ________1.3 Di electric strength of Glass epoxy material is ________1.4 Di electric constant of an Air is________1.5 PCB’s are fabricated by_______ process.2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 The thorough cleaning of particulate matters can be done by _______ process () ()a) washing b) drying c) wet brushing d) wiping () ()2.2 Remote and calculator key tabs to be plated with _______a) Silver b) Nickel c) Zinc d) Gold2.3 When PCB layer count increases, the ratio of the risk factors will be ______a) Less b) more c) Nil d) Nominal2.4 The computer generated NC drill files are needed for_______ drilling.a) CNC b) Opticals c) LASER d) Plasma2.5 ____ is the CAM software to view the gerber files..a) Camtastic b) Proload c) Orcad d) Proteus3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 B stage a. scrubbing3.2 decoupling capacitor b. Prepreg3.3 Metallic soil c. electroless plating3.4 PTH d. Inner layer3.5 Multilayer e. Ceramic f. Black oxide

Qe REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION (NEC, RNTC, JNTC, TNTC) DIPLOMA IN ELECTRONICS - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 The required thickness of the PTH is ________1.2 Di electric strength of Glass epoxy material is ________1.3 Di electric constant of an Air is________1.4 PCB’s are fabricated by_______ process.1.5 _______ file is required to drive the Photo plotter2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 Remote and calculator key tabs to be plated with _______ () ()a) Silver b) Nickel c) Zinc d) Gold () ()2.2 When PCB layer count increases, the ratio of the risk factors will be ______a) Less b) more c) Nil d) Nominal2.3 The computer generated NC drill files are needed for_______ drilling.a) CNC b) Opticals c) LASER d) Plasma2.4 ____ is the CAM software to view the gerber files..a) Camtastic b) Proload c) Orcad d) Proteus2.5 The thorough cleaning of particulate matters can be done by _______ processa) washing b) drying c) wet brushing d) wiping3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 B stage a. Prepreg3.2 decoupling capacitor b. Inner layer3.3 Metallic soil c. Ceramic3.4 PTH d. electroless plating3.5 Multilayer e. Black oxide f. scrubbing

NETTUR TECHNICAL TRAINING FOUNDATION Course : Diploma In Electronics - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MAY 2016Subject: PCB Design Total Marks : 55Subject Code: CP04 03 04 Total Time : 2H PART B1.0 ANSWER ANY TEN OF THE FOLLOWING 2*10=201. 1 Name any five top level metals of PCB?1. 2 Explain about via hole.1. 3 What is mean by wave soldering?1. 4 What is the standard thickness of PCB ?1. 5 What are the standard thickness of the Copper foil?1. 6 Write Any three Mechanical Machining operations of PCB’s?1. 7 What type of Drill bit can be used for PCB drilling?1. 8 What is the surface layer and core layer of Single side copper clad laminate?1. 9 What is the size of 1206 smd package in mm?1. 10 What is the water obsorption rate of Glass epoxy & Paper phenonic?1. 11 what are the Input data needed for 1. Auto routing 2 .CNC Drilling1. 12 Why the Grid system is used in layout designing?2.0 ANSWER ANY SIX OF THE FOLLOWING 3*6=182. 1 Define vapour degreasing.2. 2 Write about Dry film photo resist, Thickness and its Protective layers2. 3 What is meant by Buried Via?2. 4 Draw the diagram of Immersion Etching and Explain?2. 5 Name the three major process steps in SMD components assembly.2. 6 Explain about Plated Through Hole?2. 7 What is mean by organinc soil in board cleaning?2. 8 What kind of Blade used for PCB sawing?3.0 ANSWER ANY THREE OF THE FOLLOWING 4*3=123. 1 Explain about Silk screen layer with neat diagram.3. 2 Describe about the Gerber file?3. 3 How to fabricate the PREPREG or B-stage material by treating process?3. 4 Write about Gold plating and its advantages?4.0 ANSWER THE FOLLOWING 5*1=54. 1 a) Write any five PCB design rules with drawing? [use appropriate colour] OR b) Draw the Dry film structure and write its protective layers?

NETTUR TECHNICAL TRAINING FOUNDATION Course : Diploma In Electronics - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - AUGUST 2016Subject: PCB Design Total Marks : 25Subject Code: CP04 03 04 Total Time : 1H PART B1.0 ANSWER ANY SIX OF THE FOLLOWING 2*6=121. 1 What are the types of PCB’s are commonly used in the electronic Equipments?1. 2 What is the water obsorption rate of Glass epoxy & Paper phenonic?1. 3 Explain about Annula ring.1. 4 Why the Tin plating is needed on the PCB?1. 5 List the Types of VIA holes?1. 6 Name the three different plating techniques?1. 7 what are the Input data needed for 1. Auto routing 2 .CNC Drilling1. 8 Why the Grid system is used in layout designing?2.0 ANSWER ANY THREE OF THE FOLLOWING 3*3=92. 1 How to develop the UV exposed dryfilm?2. 2 Define metallic soil in board cleaning.2. 3 Explain about Plated Through Hole?2. 4 What is meant by punching of PCB's?3.0 ANSWER ANY ONE OF THE FOLLOWING 4*1=43. 1 Describe about the Gerber file?3. 2 Write the Process steps of Print and Etch process?

Qeӈ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION DIPLOMA IN ELECTRONICS - CP04 All June Batch’s & Jan 2014 Batch III SEMESTER EXAMINATION - DEC 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70 SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 PCB made with a thin Di electric material is known as _________.1.2 LASER drilled via holes are called _____________ via’s.1.3 Edge connector tabs to be plated with ____________ metal.1.4 Core layer is used as a ____________ layer of MLB.1.5 PCB mounting hole is required for an every ____________ inch.2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 The computer generated NC drill files are needed for------- drilling. () a) CNC b) Opticals c) LASER d) Plasma () ()2.2 ____________ lamp is the safe light for the Photo printing room () a) Yellow b) Green c) Blue d) UV2.3 Mechanical strength of ___________ material is high. a) Paper phenolic b) Glass epoxy c) polyster d) teflon2.4 Designator for Integrated circuit is ___________. a) IC b) U c) IU d) B2.5 Command for erasing the selected object is ___________ in Protela) Delete b) Shift Delete c) D+O d) DS3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 Cad software a. outer layer3.2 Surface layer b. Allegro3.3 Solderable metal c. Single side PCB3.4 Copper contamination d. Tin lead3.5 Domestic Appliances e. finger prints f. CNC

Qeӛ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION DIPLOMA IN ELECTRONICS - CP04 All June Batch’s & Jan 2014 Batch III SEMESTER EXAMINATION - DEC 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 PCB mounting hole is required for an every ____________ inch.1.2 Core layer is used as a ____________ layer of MLB.1.3 Edge connector tabs to be plated with ____________ metal.1.4 LASER drilled via holes are called _____________ via’s.1.5 PCB made with a thin Di electric material is known as _________.2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 Command for erasing the selected object is ___________ in Protel () ()a) Delete b) Shift Delete c) D+O d) DS () ()2.2 Designator for Integrated circuit is ___________.a) IC b) U c) IU d) B2.3 Mechanical strength of ___________ material is high.a) Paper phenolic b) Glass epoxy c) polyster d) teflon2.4 ____________ lamp is the safe light for the Photo printing rooma) Yellow b) Green c) Blue d) UV2.5 The computer generated NC drill files are needed for------- drilling.a) CNC b) Opticals c) LASER d) Plasma3.0 MATCH THE FOLLOWING 1X5=5 AB3.1 Domestic Appliances a. outer layer3.2 Copper contamination b. Single side PCB3.3 Solderable metal c. CNC3.4 Surface layer d. Tin lead3.5 Cad software e. finger prints f. Allegro

QeӮ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION DIPLOMA IN ELECTRONICS - CP04 All June Batch’s & Jan 2014 Batch III SEMESTER EXAMINATION - DEC 2016SUBJECT: PCB DESIGN & FABRICATION TOTAL MARKS: 70SUBJECT CODE: CP04 03 04 TOTAL TIME: 2H 15MIN PART-A MARKS: 15 TIME: 15MIN1.0 FILL IN THE BLANKS 1X5=51.1 Core layer is used as a ____________ layer of MLB.1.2 LASER drilled via holes are called _____________ via’s.1.3 PCB mounting hole is required for an every ____________ inch.1.4 Edge connector tabs to be plated with ____________ metal.1.5 PCB made with a thin Di electric material is known as _________.2.0 CHOOSE THE CORRECT ANSWER 1X5=5 ()2.1 Designator for Integrated circuit is ___________. () () a) IC b) U c) IU d) B ()2.2 ____________ lamp is the safe light for the Photo printing room () a) Yellow b) Green c) Blue d) UV2.3 Command for erasing the selected object is ___________ in Protela) Delete b) Shift Delete c) D+O d) DS2.4 Mechanical strength of ___________ material is high. a) Paper phenolic b) Glass epoxy c) polyster d) teflon2.5 The computer generated NC drill files are needed for------- drilling.a) CNC b) Opticals c) LASER d) Plasma3.0 MATCH THE FOLLOWING 1X5=5 A B3.1 Cad software a. CNC3.2 Surface layer b. outer layer3.3 Solderable metal c. finger prints3.4 Copper contamination d. Single side PCB3.5 Domestic Appliances e. Tin lead f. Allegro

Qe฿ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION TOTAL MARKS: 70 DIPLOMA IN ELECTRONICS - CP04 TOTAL TIME: 2H 15MIN All June Batch’s & Jan 2014 Batch MARKS: 15 TIME: 15MIN III SEMESTER EXAMINATION - DEC 2016SUBJECT: PCB DESIGN & FABRICATION 1X5=5SUBJECT CODE: CP04 03 04 1X5=5 PART-A () ()1.0 FILL IN THE BLANKS ()1.1 LASER drilled via holes are called _____________ via’s. ()1.2 Edge connector tabs to be plated with ____________ metal. ()1.3 PCB mounting hole is required for an every ____________ inch.1.4 PCB made with a thin Di electric material is known as _________. 1X5=51.5 Core layer is used as a ____________ layer of MLB.2.0 CHOOSE THE CORRECT ANSWER2.1 ____________ lamp is the safe light for the Photo printing rooma) Yellow b) Green c) Blue d) UV2.2 Mechanical strength of ___________ material is high.a) Paper phenolic b) Glass epoxy c) polyster d) teflon2.3 Command for erasing the selected object is ___________ in Protela) Delete b) Shift Delete c) D+O d) DS2.4 The computer generated NC drill files are needed for------- drilling.a) CNC b) Opticals c) LASER d) Plasma2.5 Designator for Integrated circuit is ___________.a) IC b) U c) IU d) B3.0 MATCH THE FOLLOWING B A a. finger prints b. Tin lead3.1 Cad software c. outer layer3.2 Surface layer d. Single side PCB3.3 Solderable metal e. Allegro3.4 Copper contamination f. CNC3.5 Domestic Appliances

Qeᴓ REG.NO.: NETTUR TECHNICAL TRAINING FOUNDATION TOTAL MARKS: 70 DIPLOMA IN ELECTRONICS - CP04 TOTAL TIME: 2H 15MIN All June Batch’s & Jan 2014 Batch MARKS: 15 TIME: 15MIN III SEMESTER EXAMINATION - DEC 2016SUBJECT: PCB DESIGN & FABRICATION 1X5=5SUBJECT CODE: CP04 03 04 1X5=5 PART-A () ()1.0 FILL IN THE BLANKS ()1.1 Edge connector tabs to be plated with ____________ metal. ()1.2 PCB mounting hole is required for an every ____________ inch. ()1.3 PCB made with a thin Di electric material is known as _________.1.4 Core layer is used as a ____________ layer of MLB. 1X5=51.5 LASER drilled via holes are called _____________ via’s.2.0 CHOOSE THE CORRECT ANSWER2.1 Mechanical strength of ___________ material is high.a) Paper phenolic b) Glass epoxy c) polyster d) teflon2.2 Command for erasing the selected object is ___________ in Protela) Delete b) Shift Delete c) D+O d) DS2.3 The computer generated NC drill files are needed for------- drilling.a) CNC b) Opticals c) LASER d) Plasma2.4 Designator for Integrated circuit is ___________.a) IC b) U c) IU d) B2.5 ____________ lamp is the safe light for the Photo printing rooma) Yellow b) Green c) Blue d) UV3.0 MATCH THE FOLLOWING B A a. Tin lead b. Single side PCB3.1 Cad software c. Allegro3.2 Surface layer d. outer layer3.3 Solderable metal e. CNC3.4 Copper contamination f. finger prints3.5 Domestic Appliances

NETTUR TECHNICAL TRAINING FOUNDATION Course : Diploma In Electronics - CP04 All June Batch’s & Jan 2014 BatchIII SEMESTER SUPPLEMENTARY EXAMINATION - DECEMBER 2016Subject: PCB Design Total Marks : 55Subject Code: CP04 03 04 Total Time : 2H PART B1.0 ANSWER ANY TEN OF THE FOLLOWING 2*10=201. 1 Name any five top level metals of PCB?1. 2 Explain about Annula ring.1. 3 Write any five types of resins to fabricate the copper clad laminates?1. 4 What are the standard thickness of the Copper foil?1. 5 Write about Flexible PCB and its applications1. 6 Explain about via hole.1. 7 What is the standard thickness of PCB ?1. 8 What is the surface layer and core layer of Single side copper clad laminate?1. 9 What kind of Light source is used for Dryfilm exposing?1. 10 What are the types of PCB’s are commonly used in the electronic Equipments?1. 11 what are the Input data needed for 1. Auto routing 2 .CNC Drilling1. 12 Why the Grid system is used in layout designing?2.0 ANSWER ANY SIX OF THE FOLLOWING 3*6=182. 1 What is mean by Net list?2. 2 Explain about Di electric strength of copper clad laminate?2. 3 Draw the flow chart of pcb layout design?2. 4 Write about Multi layer PCB and its applications?2. 5 What are the 4 types of Etching chemicals?2. 6 Define metallic soil in board cleaning.2. 7 Write about Gold plating and its advantages?2. 8 Explain about Plated Through Hole?3.0 ANSWER ANY THREE OF THE FOLLOWING 4*3=123. 1 Explain about Silk screen layer with neat diagram.3. 2 Describe about the Gerber file?3. 3 How to fabricate the PREPREG or B-stage material by treating process?3. 4 Why the solder masking is needed to the pcb’s?4.0 ANSWER THE FOLLOWING 5*1=54. 1 a) Define the process of copper foil manufacturing by electrolytic method? OR b) What is mean by Etching? Explain about Spray Etching process with neat sketch?

NETTUR TECHNICAL TRAINING FOUNDATION Course : Diploma In Electronics - CP04 III SEMESTER SUPPLEMENTARY EXAMINATION - MARCH 2017Subject: PCB Design Total Marks : 50Subject Code: CP04 03 04 Total Time : 2H 2*8=16 PART B1.0 ANSWER ANY EIGHT OF THE FOLLOWING1. 1 What type of Drill bit can be used for PCB drilling?1. 2 Explain about Annula ring.1. 3 Name the three different plating techniques?1. 4 What are the standard thickness of the Copper foil?1. 5 Write any four PCB designing software’s?1. 6 Name any five top level metals of PCB?1. 7 What is the thickness of 6layer Multilayer board?1. 8 What is mean by wave soldering?1. 9 what are the Input data needed for 1. Auto routing 2 .CNC Drilling1. 10 What are the types of PCB’s are commonly used in the electronic Equipments?2.0 ANSWER ANY SIX OF THE FOLLOWING 3*6=182. 1 What is meant by Blind via?2. 2 Write about Multi layer PCB and its applications?2. 3 What are the 4 types of Etcing chemicals?2. 4 Draw the flow chart of pcb layout design?2. 5 How to develop the UV exposed dryfilm?2. 6 Explain about Plated Through Hole.2. 7 Define metallic soil in board cleaning.2. 8 Why the solder masking is needed to the pcb’s?3.0 ANSWER ANY FOUR OF THE FOLLOWING 4*4=163. 1 How to fabricate the PREPREG or B-stage material by treating process?3. 2 Explain about Bubble Etching with neat Diagram?3. 3 Describe about the Gerber file?3. 4 Write about Gold plating and its advantages?3. 5 Write any five PCB design rules with drawing? [use appropriate colour]3. 6 Draw the Dry film structure and write its protective layers?

UNIEAGLE-BASI

IT-1IC CONCEPTS

1.1 INTRODUCTION TO PCIndustry standards for PCB desiby IPC (formerly known as InstitutPackaging Electronic Circuits).PCB softwares: EAGLE Altium Designer ExpressPCB PCBWeb Designer Kicad

CB SOFTWARES ign are set and controlled te for Interconnecting and

1.2 INTRODUCTION TO EAEAGLE - Easily Applicable Grapsoftware by Autodesk.Use EAGLETo draw the schematicTo make the PCB

AGLE phical Layout Editor, is a design

1.3 SECTIONS OF THE SCTool Box: It consists of a ndesigning schematics. Tool Specific Options: Some tools have their speThese are displayed above tyou have selected the tool. Command Line:you can athis space to select tools, ch

CHEMATIC EDITOR number of useful tools for ecific settings and options. the command line once also type in commands in hange settings, etc

Sheet Display: A schematto 99 schematic sheetsWorkspace: This is the aryour components and shapGrid Size and Coordinate Grid size refers to the minyou can move/place any com

tic file in EAGLE can hold uprea where you will placepe up your schematic. Display:nimum distance apart that mponent