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Which lamination methods are used to make PCB multi-layer boards better?

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  The pcb multi-layer board is a relatively messy circuit board, and there are many ways to limit the layer. What kind of lamination method is used for PCB multi-layer board to make it better? Today, the ceramic substrate is compiled to share the lamination methods, and each has its own advantages;


Ceramic substrate


  Kraft Paper Kraft Paper

  When the multi-layer board or the substrate board is pressed (laminated), the kraft paper is used as a heat transfer buffer. It is placed between the platen of the press and the steel plate to smooth the temperature rise curve closest to the bulk material. Between multiple substrates or multilayer boards to be pressed. Try to get close to the temperature difference between the layers of the board. The commonly used specifications are 90 lbs to 150 lbs. Because the fiber in the paper has been crushed after high temperature and high pressure, it is no longer resistant and difficult to function, so it is necessary to try to replace it. The kraft paper is co-cooked with a mixture of pine and various strong alkalis, and after the volatiles escape and the acid is removed, it is washed and precipitated immediately; after it becomes pulp, it can be restricted to become rough and cheap paper. material.

  Kiss Pressure, pressure, low pressure

  When the multi-layer board is pressed, when the plates in each opening are placed and positioned, the opening end is heated and lifted from the lowermost hot plate, and the strong hydraulic top column (Ram) is lifted upward to press the openings ( The bulk material in Opening) is bonded. At the moment, the beginning of the combined film (Prepreg) gradually softens and even flows, so the pressure used for the top extrusion is not too large, preventing the sheet from slipping or the amount of glue flowing out too much. This initial selection of lower pressure (15 to 50 PSI) is called "kiss pressure". However, when the resin in the film material is softened and softened by heat, and will be hardened, it is necessary to progress to full pressure (300 to 500 PSI), so that the bulk materials reach a tight bond to form a solid multilayer board.

  Foil Lamination copper foil plate method

  Refers to the mass production multi-layer board, the outer layer of copper foil and film directly pressed with the inner layer skin, which becomes the multi-layer board multi-plate large mass plate method (Mass Lam), to replace the previous single-sided thin substrate tradition Pressure law

  Crease wrinkles

  In the lamination of a multi-layer board, it is often referred to as the wrinkles that occur when the copper skin is not handled. Thin copper sheets below 0.5 oz are more prone to such defects when laminated

  Cap Lamination cap pressure method

  It refers to the traditional lamination method of the previous multi-layer PCB board. At that time, the "outer layer" of the MLB was superimposed and pressed on a thin substrate with single-sided copper skin. It was not until the end of 1984 that the output of the MLB was greatly increased. The current copper-type large or many compression laws (Mss Lam). This MLB compression method, which uses a single-sided copper-thin substrate, is called Cap Lamination.

  Dent fall

  Refers to the gentle and uniform subsidence on the copper surface, which may be caused by the partial shape of the steel plate used for pressing. If there is a drop in the edge type of the fault, it is called Dish Down. If these defects are unfortunately left on the line after the copper is etched, the impedance of the high-speed transmission signal will be unstable, and noise Noise will occur. Therefore, the copper surface of the substrate should be prevented as much as possible.

  Autoclave pressure cooker

  It is a container filled with high-temperature saturated water vapor and can apply high pressure. The laminated substrate (Laminates) sample can be placed for a period of time, forcing water to enter the plate, and then taking out the plate. It is placed on the surface of high-temperature molten tin to measure its "layering resistance". This word is also a synonym for Pressure Cooker, which is more commonly used in the industry. In addition, in the multi-layer plate pressing process, there is a "cabin pressure method" which is carried out with high temperature and high pressure carbon dioxide, and is also classified as such Autoclave Press.

  Mass Lamination Large Plate (Lamination)

  This is a new construction method in which the multi-layer plate pressing process discards the "alignment tip" and selects multiple rows of plates on the same surface. Since 1986, when the demand for four or six-layer boards has increased, the pressing method for multi-layer boards has been greatly changed. In the previous period, only one shipment board was placed on a process board to be pressed. This one-to-one dominance has been broken in the new law. It can be changed to one-two, or one-to-four, or even more according to its size. The plates are pressed together. The second method is to abolish the register tips of various bulk materials (such as inner sheet, film, outer single sheet, etc.); and the outer layer is changed to copper foil, and the "target" is pre-made on the inner layer. After the pressure is pressed, the target is "swept", and the tool hole is drilled from the center of the hole, and the hole can be drilled on the drill bed.

  Lay Up overlay

  Before the lamination of the multi-layer circuit board or substrate, it is necessary to complete the vertical alignment, the alignment, or the registration work of the inner layer board, the film and the copper skin, and the steel plate and the kraft paper padding. It can be carefully fed into the press for hot pressing. This preparatory work is called Lay Up. In order to improve the quality of the multi-layer board, not only the "superimposing" work should be carried out in the clean room controlled by temperature and humidity, but for the speed and quality of mass production, the general platen method is generally adopted for the eight layers or less (Mass Lam) ) Construction, and even the need to use "automation" superposition to reduce human error. In order to save the plant and the use of equipment, the general factory has combined the "superimposed" and "folded" into a comprehensive processing unit, so the automation of the project is appropriate.

  The above-mentioned ceramic substrate Xiaobian shared the layer limitation of the PCB multi-layer board. The method of use can be based on the customer's product needs and the comprehensive utilization of its own resources, and try to help customers make high-quality products and supply high-quality customers.
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