In 1950, the first panel appeared. The single-panel material was made of paper phenolic substrate. The simple understanding of the double panel is that there are wiring on both sides. This makes it better. The multi-panel refers to more than 2 layers. Price, please see below
The history of single-sided boards:
The single-sided printed circuit board was developed in the United States in the early 1950s with the advent of crystals. At that time, the main production method was the direct etching method of copper foil. From 1953 to 1955, Japan used imported copper foil to make a paper phenolic copper foil substrate for the first time, and it was widely used in the radio. In 1956, after the appearance of Japanese circuit board specialists, the manufacturing technology of single-panel was rapidly progressing.
In terms of materials, paper phenolic copper foil substrates were mainly used in the early days. However, due to the low electrical insulation of phenolic materials, poor solder heat resistance and distortion, materials such as paper-based epoxy resin and glass epoxy resin were successively The single panel required for the development of consumer electronic devices is almost entirely made of paper phenolic substrate.
Single panel features:
The single panel is on the most basic PCB, with the parts concentrated on one side and the wires concentrated on the other side. Because the wire only appears on one side, we call this PCB a single-sided. Because single-panel has many strict restrictions on the design line (because there is only one side, the wiring can not cross and must be around the original path), so only the early circuit used this type of board;
The single-panel wiring diagram is mainly based on screen printing, that is, a resist is printed on the surface of the copper, and after etching, the mark is printed with a solder resist, and finally the via hole is finished by punching. shape. In addition, some of the products produced in small quantities and diversely use a photoreceptor to form a pattern.
Double-sided circuit board
Double-Sided Boards have wiring on both sides. However, to use the wires on both sides, it is necessary to have proper circuit connections between the two sides. The “bridge” between such circuits is called a via. The via hole is a small hole filled or coated with metal on the PCB, which can be connected to the wires on both sides. Because the area of the double panel is twice as large as that of the single panel, and because the wiring can be interlaced (can be wound around the other side), it is more suitable for circuits that are more complex than single panels.
Strictly speaking, the double panel is a very important PCB board in the circuit board. His use is very big. It is very simple to see whether a PCB board is a double panel. I believe that friends can fully understand the single panel. Grasping, the double panel is the extension of the single panel, which means that the single panel line is not enough to turn to the reverse side. The important feature of the double panel is that there is a through hole. Simply put, it is double-sided routing, both sides have lines! One sentence is that the double-sided board is a double panel! Some friends have to ask, for example, a double-sided board, but only one side has electronic parts, is this board a double-panel or a single-panel? The answer is obvious. Such a board is a double-panel, just a part of the double-panel board.
Multi-layer circuit board simple distinction
The circuit board determines the process difficulty and processing price according to the number of wiring faces. The common circuit board is divided into single-sided routing and double-sided routing, commonly known as single-panel and double-panel, but high-end electronic products are restricted by product space design factors. In addition to the surface wiring, a multi-layer circuit can be stacked inside. During the production process, each layer of the line is fabricated, and then positioned by an optical device, pressed, and the multi-layer line is superimposed on a circuit board. Commonly known as multi-layer circuit board. Any circuit board that is greater than or equal to 2 layers can be called a multilayer circuit board. Multi-layer circuit boards can be further divided into multi-layer rigid circuit boards, multi-layer hard and soft circuit boards, and multi-layer soft and hard circuit boards.
The birth of multilayer boards
The increased concentration of integrated circuit packages leads to a high concentration of interconnect lines, which necessitates the use of multiple substrates. Unpredictable design issues such as noise, stray capacitance, crosstalk, etc. occur in the layout of printed circuits. Therefore, printed circuit board design must focus on minimizing signal line length and avoiding parallel paths. Obviously, in a single panel, even in a double panel, these requirements cannot be satisfactorily answered due to the limited number of crossovers that can be achieved. In the case of a large number of interconnections and cross-over requirements, in order to achieve a satisfactory performance, the board must be expanded to more than two layers, resulting in a multilayer board. The original intent of fabricating multilayer boards is therefore to provide more freedom in selecting suitable routing paths for complex and/or noise-sensitive electronic circuits. The multilayer circuit board has at least three conductive layers, two of which are on the outer surface and the remaining one is synthesized in the insulating plate. The electrical connection between them is usually achieved by plated through holes in the cross section of the board. Unless otherwise stated, a multilayer printed circuit board, like a double panel, is typically a plated through hole plate.
Multilayer boards are manufactured by stacking two or more circuits on each other with reliable pre-set interconnections. Since drilling and plating have been completed before all the layers have been rolled together, this technique has violated the traditional manufacturing process from the beginning. The innermost two layers are made up of traditional double panels, while the outer layers are different, they are made up of separate single panels. Prior to rolling, the inner panel will be drilled, through-hole plated, patterned transferred, developed, and etched. The outer layer to be drilled is a signal layer that is plated in such a way as to form a balanced copper ring at the inner edge of the through hole. The layers are then laminated together to form a multi-substrate which can be interconnected using wave soldering (between components).
Rolling may be done in a hydraulic press or in an overpressure chamber (autoclave). In the hydraulic press, the prepared material (for pressure stacking) is placed under cold or preheated pressure (high glass transition temperature material is placed at a temperature of 170-180 ° C). The glass transition temperature is the amorphous region of the amorphous polymer (resin) or portion of the crystalline polymer that changes from a hard, relatively brittle state to a viscous, rubbery temperature.
Multi-layer boards are put into use in professional electronic equipment (computers, military equipment), especially in the case of weight and volume overload. However, this can only be achieved by increasing the cost of the multi-layer board in exchange for space increase and weight reduction. Multilayer boards are also very useful in high-speed circuits, which provide designers of printed circuit boards with more than two layers of boards to route wires and provide large ground and power areas.