PCB Multilayer Pressing Production Process

1.Autoclave Pressure Pot It is a container filled with high temperature saturated water vapor capable of applying high air pressure. It can hold laminate samples in it for a certain period of time to force moisture into the sheet, then remove the samples and place them on a high-temperature molten tin surface to measure their delamination resistance. It is also synonymous with PressureCooker and is widely used in the industry. In addition, the high-temperature, high-pressure carbon dioxide chamber press method of the lamination process also belongs to this type of press.

2. Pressure cover method

It refers to the traditional layering method of early multilayer PCB boards. At that time, the outer layer of the MLB is laminated and single-sided copper skin thin substrate pressing, using the existing copper cladding large-scale or large-scale lamination (mlam). This early MLB lamination using thin single sided copper substrates was called lamination.

3 Crease Folding

In multilayer pcb fabrication lamination, it often refers to copper skin folds when not handled properly. This drawback is more likely to occur when thin copper skins below 0.5oz are laminated into multiple layers.

4. Dents Dents are gentle, uniform depressions that appear on the surface of the copper and may be caused by localized pitting of the steel plate used for pressing. If there is a neatly descending edge of the fault, it is known as subsidence. If these flaws unfortunately remain on the line after copper corrosion, the impedance of the high-speed transmitted signal will be unstable, resulting in noise. Therefore, such defects should be avoided on the copper surface of the substrate as much as possible.

5, CaulPlate Separator Multilayer plate in the press, in the pressure bed of each student opening (Opening), often stacked down many books to be pressed boards of loose material (such as 8 ~ 10 sets), each set of loose material (Book), to flat surface smooth and hard stainless steel plate can be divided into, this spatial separation with a mirror as well as stainless steel plate can not be called CaulPlate or SeparatePlate, currently commonly used in China are AISI430 or AISI630, etc..

6. Laminated copper foil method, refers to the mass production of multi-layer composite panels,PCB factory in which the outer layer of copper foil and film directly pressed on the inner layer of the laminate to form a multi-row MassLam multi-layer composite plate method, replacing the traditional single-sided thin substrate lamination method.

7.KraftPaper KraftPaper multilayer or substrate board pressing (lamination), kraft paper as a heat transfer cushion. It is placed between the flat and steel plates of the press to moderate the temperature rise profile closest to the bulk material. Between the multiple substrates or multilayers to be pressed. It is used to bring the temperature difference between the layers of the sheet as close as possible, and is commonly used in sizes from 90 pounds to 150 pounds. Because the fibers in the paper have been crushed by the high temperature and pressure, they are no longer tough enough to function and must be replaced with new ones. This kraft paper is made by boiling pine wood with a mixture of various strong bases, then washing and precipitating after the volatiles have escaped and the acid has been removed. After it is turned into pulp, it can be pressed again and become rough and cheap paper.

8, Kissing pressure, low pressure, multilayer board in the press, when all the boards in the openings are placed in position, it begins to heat up, from the bottom of the hot board, a strong hydraulic pressure plug (Ram) upward in each opening of the bulk material is bonded to the pressure. At this point as the film (prepreg) begins to soften and flow uniformly, so the top squeeze pressure used should not be too high to avoid sheet slippage or excessive glue flow. Such a low initial pressure (15-50 psi) is referred to as the kissing pressure. However, as the resin in each film is softened and gelatinized by heat and is about to harden again, the total pressure (300-500 PSI) must be increased so that each piece of loose material comes close to forming a solid multilayer sheet.

9. Overlap Stacking

Multilayer design circuit boards or substrates in the press, the need for inner laminates, film and copper skin and other loose materials and steel, kraft paper padding, etc., to complete the enterprise up and down the target alignment, fall in line, or set of work, in order to prepare for the students will be able to be more careful to send into the press for different hot press. This kind of preparatory work can be called LayUp, in order to improve the quality of multilayer boards, not only is there no such stacking analysis staff to be carried out in the environment of temperature and humidity automatic control of the clean room, but also in order to realize the speed and quality of mass production, generally an eight-layer or less are used in large-scale movable press (MassLam) construction, and even the development of the need for the use of Chinese We have also developed an automated stacking structure to minimize human error. In order to achieve savings in production plants and joint system equipment for safety reasons, are generally factories will be stacked and folded boards between the two merger of the issue of people with a comprehensive information processing technology unit, so its automation of the project management is quite important and complex.　　10, MassLamination large-scale pressure plate (laminated) This is a multi-layer plate pressing process has given up the alignment of the tip, and the use of the same horizontal plane based on multiple rows of boards of the new building construction method. Since 1986 when the four, six-layer board demand increased under the tear, multi-layer board pressing method has changed a lot. Earlier a to be pressed on the process board only a row of shipping board, such a one-to-one arrangement in the new law has been an effective breakthrough, according to its size and the size of the company into such a pair of two, or a pair of four, and even more rows of boards for the press. The new law is the second is the country to cancel the use of a variety of loose material (such as the inner sheet, film, outer electronic single-sided sheet, etc.) of the registration tip; and will change the outer layer of copper foil, and first pre-do the target on the inner layer of the board, in order to wait for the pressure to close that is the sweep out of the target, and then from the center of the tool holes drilled, can be set up in the drilling machine for the study of the drill holes.