Special Processing of PCB Circuit Board
PCB processing special process as in the field of PCB industry, for PCB copy board, PCB design process must be skilled.
Through the analysis and summary of our professional PCB board-copying professionals, our professional PCB board-copying experts come to the following PCB processing special process, hoping to help people in the PCB industry.
Additive Process
It refers to the direct growth of local conductor lines on the surface of non-conductor substrates with the assistance of additional resistors (see PCB Information Journal, No. 47, P. 62).
The Additive Process used in PCB sheeting can be divided into full addition, semi-addition and partial addition.
Backpanels, Backplanes Support Board
It is a kind of thick circuit board (such as 0.093 ", 0.125"), which is specially used to connect other boards.
The method is to insert the connector into the pressing through hole, but not solder, and connect the connector through the guide pins of the board one by one in a winding way. Connector can be inserted into the general PCB board. Because of this special board, its through hole can not be soldered, but let the hole wall and guide needle clamp directly, so its quality and aperture requirements are particularly stringent, its order quantity is not very large, general circuit board factories are unwilling and easy to accept such orders, almost become a high-grade specialized industry in the United States.
Build Up Process Layered Process
This is a new field of thin multi-layer plate approach, the earliest enlightenment was from IBM's SLC process, which was started in 1989 at its Yasu factory in Japan.
This method is based on the traditional double-panel method. The liquid photosensitive precursor, such as Probmer 52, is coated on the two outer panels. After semi-hardening and photolysis, a shallow photosensitive guide hole (Photo-Via) connected with the next bottom layer is made, and then the conductor layer is added by chemical copper and electroplating copper. After line imaging and etching, the liquid photosensitive precursor is coated on the two outer panels. New wires and buried or blind holes interconnected with the bottom can be obtained.
By adding layers repeatedly, the required number of layers can be obtained. This method can not only avoid the expensive cost of mechanical drilling, but also reduce the aperture to less than 10 mil.
Over the past five to six years, various kinds of multi-layer board technologies that break through the tradition and increase layer by layer have been promoted by American, Japanese and European companies, making these Build Up Processes famous, and more than ten kinds of products have been listed.
In addition to the above-mentioned "photosensitive pore forming", there are different "pore forming" ways for alkaline chemicals, Laser Ablation and plasma Etching of organic sheets after removing copper skin.
In addition, a new type of Resin Coated Copper Foil coated with semi-hardening resin can be used to make finer, smaller and thinner multilayer plates by means of Sequential Lamination.
In the future, diversified personal electronic products will become the world of this kind of real light, thin and small multi-layer board.
Cermet pottery gold mixes ceramic powder with metal powder and adds adhesives as a kind of coating. It can be printed on the surface (or inner layer) of the circuit board by thick film or thin film as a "resistor" layout and placement to replace the external resistor when assembled.
Co-Firing Co-firing
It is a process of mixing ceramic into PCB circuit board (Hybrid). The printed circuits of various precious metal thick film pastes (Thick Film Paste) on the small board are fired at high temperature. All kinds of organic carriers in thick film paste are burned off, leaving precious metal conductors as interconnection wires.
Crossover intersection, intersection of two vertical and horizontal conductors, intersection point drop filled with insulating medium. Generally, the top and bottom wiring of single-panel green paint with carbon film jumper or Layer-adding method belongs to such "crossover".
Discreate Wiring Board Scattered PCB Circuit Board, Double Circuit Board
Another expression of Multi-Wiring Board is that round enameled wires are attached to the surface of the board with through holes. The performance of the multiplex board in high frequency transmission line is better than that of the flat square line etched by PCB.
DYCOstrate plasma etching hole layer-increasing method
It is a Build up Process developed by Dyconex Company in Zurich, Switzerland. The copper foil at each hole position on the plate surface is first etched, then placed in a sealed vacuum environment, and filled with CF4, N2, and O2 to form plasma with high activity at high voltage, which is used to etch the substrate at the perforated position and to produce tiny guide holes (less than 10mil). Its commercial process is called DYCOstrate.
Electro-Deposited Photoresistor Electrophoretic Photoresistor
It is a new construction method of "photoresist". It was originally used in the field of "electro-painting" for complex metal articles, but recently it was introduced into the application of "photoresist". In this method, photosensitive charged resin colloidal particles are uniformly plated on the copper surface of PCB circuit board as an anti-etching inhibitor. At present, it has been put into mass production in the process of direct copper etching of inner plate.
According to the different operation methods, the ED photoresistance can be placed in the anode or cathode respectively. It is called "anode electro-photoresistance" and "cathode electro-photoresistance". According to the principle of photosensitization, there are two types of photosensitization: Negative Working and Positive Working.
At present, the negative ED photoresistor has been commercialized, but it can only be used as a planar resistor. Because of the difficulty of photosensitivity in the through hole, it can not be used for image transfer of the outer panel. As for the "normal ED" which can be used as photoresistor for outer panel (because it belongs to the photosensitive decomposition skin film, the hole wall is not sufficiently sensitive but has no effect), Japanese manufacturers are still stepping up their efforts at present, hoping to develop commercial mass production applications, so that the production of thin lines is relatively easy to achieve. This term is also known as "Electrothoretic Photoresist".
Flush Conductor Embedded Circuit, Flat Conductor
It is a special PCB circuit board with flat appearance and all conductor lines are pressed into the board.
The method of single panel is to etch part of copper foil on semi-cured substrate by image transfer method to get the circuit. At the same time, the hardening operation of the board resin can be completed, and the circuit board will be all flat when the line is retracted into the surface. Usually, a thin copper layer needs to be slightly eroded on the retracted circuit surface so that a nickel layer of 0.3 mil, a rhodium layer of 20 inches, or a gold layer of 10 inches can be coated separately, so that the contact resistance can be lower and easier to slide when sliding contact is carried out. But this method is not suitable for PTH, in order to prevent the through hole from breaking when pressing in, and it is not easy for this kind of board to achieve a completely smooth surface, nor can it be used at high temperature, in order to prevent the line from pushing out of the surface after resin expansion. This technology is also called Etch and Push method. The completed board is called Flush-Bonded Board. It can be used for special purposes such as Rotary Switch and Wiping Contacts.
Frit glass melt in thick film paste (PTF) printing paste, in addition to precious metal chemicals, need to add glass powder, in order to play a coagulation and adhesion effect in high temperature incineration, so that blank ceramic substrate printing paste, can form a solid precious metal circuit system.
Fully-Additive Process
It is a method of growing selective circuits on completely insulated sheets by electroless metal deposition (mostly chemical copper), which is called "total addition method". Another incorrect statement is the "Fully Electroless" method.
Hybrid Integrated Circuit
It is a kind of circuit which applies precious metal conductive ink to a small ceramic thin substrate by printing, then burns the organic matter in the ink at high temperature, leaving a conductor circuit on the board surface, and can weld the surface bonded parts. It is a kind of circuit carrier between printed circuit board and semiconductor integrated circuit, and belongs to thick film technology. It was used for military or high-frequency applications in the early years. In recent years, because of its high price and decreasing military use, and its difficulty in automation production, as well as the increasingly miniaturized and precise circuit boards, the growth of this Hybrid is much worse than that of its early years.
Interconnect conductor
Interposer refers to any two-layer conductor that is carried by an insulating body, and the conductor to be connected by filling in some conductive fillers is called Interposer. For example, in the bare holes of multilayer board, if filled with silver paste or copper paste instead of the orthodox copper hole wall, or vertical single conductive adhesive layer and other materials, all belong to this kind of Interposer.
Laser Direct Imaging, LDI Laser Direct Imaging
Instead of exposing the negative film to transfer the image, the plate that has been pressed onto the dry film is directly scanned by a computer to direct the laser beam on the dry film. Since the parallel light emitted is a single beam of concentrated energy, the lateral wall of the dry film after imaging can be made more vertical. However, the method can only work on each plate individually, so the production speed is much faster than that of using negative film and traditional exposure. LDI can only produce 30 medium-sized panels per hour, so it can only appear occasionally in prototype proofing or high unit price panels. Because of the high cost of congenital, it is difficult to promote it in the industry.
Laser Processing
There are many precise processes in the electronic industry, such as cutting, drilling, welding, welding and so on. They can also be carried out with the energy of laser light, which is called laser processing method. The so-called LASER refers to the abbreviation of "Light Amplification Stimulated Emission of Radiation", which is translated freely by the mainland industry as "laser", which seems to be more relevant than transliteration. Laser was produced in 1959 by T. H. Maiman, an American physicist, using a single beam of light to emit laser light on ruby. Over the years, research has created a new processing method. In addition to the electronic industry, it can also be used in medical and military fields.
Micro Wire Board
Enamelled wire with circular cross section attached to the board surface (encapsulated wire) is made into a special circuit board with PTH to complete interlayer interconnection. It is commonly known as Multiwire Board "multiplex board" in the industry. When the wiring density is very high (160-250in/in2), and the diameter of the wire is very small (below 25mil), it is also called micro-encapsulated circuit board.
Moulded Circuit
Using three-dimensional die to complete the manufacturing process of three-dimensional circuit board by injection moulding or transformation method, it is called Moulded circuit or Moulded Interconnection Circuit.
Multiwiring Board (or Discrete Wiring Board)
It refers to the multi-layer interconnection circuit board, which is made by using very fine enameled wire, directly carrying out three-dimensional cross-wiring on the copper-free plate surface, and then fixing by gluing, drilling and plating holes. It is called "double-wire board". This is developed by American Merchant PCK Company. At present, Japanese Merchant Hitachi Company is still in production. This kind of MWB can save design time and is suitable for a small number of types of machines with complex circuits (a special article in issue 60 of the Journal of Circuit Board Information).
Noble Metal board
It is a conductive paste for thick film circuit printing. When it is printed on the ceramic substrate by screen printing, and then burned off the organic carrier by high temperature, a fixed precious metal circuit appears. The conductive metal powders added to the paste must be precious metals in order to avoid the formation of oxides at high temperatures. All precious metals such as gold, platinum, rhodium, palladium or other metals are used in the commodity.
Pads Only Board
In the early age of through-hole insertion, in order to ensure solderability and circuit safety, some high-reliability multilayer boards only left through-hole and welding ring outside the board, but hid interconnected lines in the next inner layer. This kind of plate with more than two layers will not be printed and weld-proof green paint, which is particularly exquisite in appearance and strict in quality inspection. At present, due to the increase of wiring density, many portable electronic products (such as Big Brother Mobile Phone) only leave SMT pads or a few lines on their PCB surface, while many interconnected dense wires are embedded in the inner layer, and high-difficulty blind holes or "Pads On Hole" are used as interconnections to reduce the total through holes to grounding and grounding. Due to the damage of copper surface with high voltage, the SMT sealing plate is also the only type of cushion plate.
Polymer Thick Film (PTF)
It refers to the precious metal paste used in ceramic thick film circuit boards to make circuits, or the paste used to form printed resistive films. The process includes screen printing and subsequent high temperature incineration. After burning off the organic carrier, there will be a firmly attached circuit system, which is commonly known as Hybrid Circuits.
Semi-Additive Process
It refers to the process of growing the required circuit directly on the insulating substrate surface by chemical copper and then continuing to thicken by electroplating copper, which is called "semi-addition". If chemical copper method is used for all circuit thickness, it is called "total addition" process. Note that the above definition is derived from IPC-T-50E, the latest specification issued since 1992.7. It is different from the original IPC-T-50D (1988.11). The early "D" version and the industry's general term refer to the non-conducting bare substrates, or on the existing thin copper foil (Thinfoil such as 1/4 oz or 1/8 oz) substrates. The image transfer of negative resistor is prepared, and then the required circuit is thickened by chemical copper or electroplating copper. The new 50E does not mention the words "thin copper skin". There is a big gap between the two statements. It seems that readers should follow the progress of the times.
Substractive Process
It refers to the removal of some useless copper foil on the surface of the substrate, which is called the "subtraction method" to achieve the circuit board. It has been the mainstream of the circuit board for many years. In contrast to another "addition" method, which directly adds copper-plated conductors to copper-free substrates.
Thick Film Circuit
PTF PolymerThick Film Paste, which contains precious metals, is printed on ceramic substrates (e.g. aluminium trioxide) and then firing at high temperature to make it a circuit system with metal conductors, which is called "thick film circuit". It belongs to a small Hybrid Circuit board. Silver Paste Jumper on one-sided PCB also belongs to thick film printing, but it does not need high temperature firing. The circuit printed on the surface of various substrates must be 0.1 mm [4 mil] thick before it is called "thick film" circuit. The manufacturing technology of this kind of "circuit system" is called "thick film technology".
Thin Film Technology
Refers to the conductor and interconnection circuit attached to the substrate, whose thickness is less than 0.1 mm [4 mil], can be vacuum evaporation, pyrolysis Coating, Cathodic Sputtering, Chemical Vapor Deposition, electroplating, anodic treatment, etc. The producer is called "thin film technology". Practical products include Thin Film Hybrid Circuit and Thin Film Integrated Circuit.
Transfer Laminated Circuit
It is a new type of circuit board production method, which uses a 93 mil thick treated smooth stainless steel plate to transfer the pattern of negative dry film first, and then high-speed copper plating on the circuit. After stripping the dry film, the stainless steel surface of the circuit can be pressed on the semi-hardened film at high and medium temperature. After the stainless steel plate is dismantled, the embedded circuit board with flat surface can be obtained. The subsequent drilling and plating holes can be drilled to obtain interlayer interconnection. CC-4 Copper Complexer 4; full addition method developed by PCK Company in the United States for special copper-free substrates (detailed introduction in Issue 47 of the Journal of Circuit Board Information); ED Electro-Deposited Photoresist; Electro-optic resistance IVH Interstitial Via Hole; Local interlayer conduction holes (finger buried through holes and blind through holes, etc.) MLC Multilayer Cer Polymer Thick Film; Polymer Thick Film; Polymer Thick Circuits; Surface Laminar Circuits of Polymer Thick Film Circuits; Surface Laminar Circuits of IBM Yasu Laboratory, Japan, 1993. The new technology, published in June 2000, is to use Curtain Coating green paint and electroplated copper to form several layers of interconnected lines outside the double panels. It is no longer necessary to drill and plated holes in the sheets.
