At present, many people think that the pcb multi-layer board making process is super complicated and difficult to understand, but what should I do if I don’t know what I need to do and I can’t learn? Today, let Xiaobian make it easy for you to get tips for making multilayer pcb. Don’t think how difficult this is! Don’t believe me, keep reading below:
At present, PCB is mostly made by subtractive method, that is, the excess copper foil on the raw material copper clad laminate is subtracted to form a conductive pattern. The subtraction method is mostly chemical etching, which is the most economical and efficient. There is no difference in chemical attack, so it is necessary to protect the required conductive pattern. A layer of resist should be coated on the conductive pattern, and then the unprotected copper foil corrosion should be subtracted. In the early stage, the resist was finished by printing the resist ink in the form of lines by screen printing, so it was called “printed circuit board”. However, with the increasing precision of electronic products, the image resolution of printed circuit can’t meet the product requirements, and then photoresist is used as the image analysis material. Photoresist is a kind of photosensitive material, which is sensitive to a certain wavelength light source, and forms a photochemical reaction with it to form a polymer. It is only necessary to selectively expose the pattern with a pattern negative, and then peel off the unpolymerized photoresist with a developer (for example, 1% sodium carbonate solution) to form a pattern protection layer.
In addition, the interlayer conduction function is realized through metallized holes, so it is necessary to drill holes in the PCB manufacturing process, and metallize and electroplate the holes to finally realize interlayer conduction.
The manufacturing process of conventional 6-layer circuit board is summarized as follows:
First, make two non-porous double panels:
Material cutting (raw material double-sided copper clad laminate)-inner layer pattern making (forming pattern resist layer)-inner layer etching (subtracting excess copper foil)
Secondly, two manufactured inner core boards are bonded and pressed by epoxy resin glass fiber prepreg.
Two inner core boards are riveted with the prepreg, and then a copper foil is laid on both sides of the outer layer, which is pressed by a press at high temperature and high pressure, so that they are bonded. The key material is prepreg, which has the same composition as the original material, and is also epoxy resin glass fiber, except that it is in an incomplete curing state and will liquefy at 7-80 degrees, in which a curing agent is added, and it will cross-link with the resin to cure at 150 degrees, and then it will not be reversible. Through such a semi-solid-liquid-solid transformation, adhesive bonding is completed under high pressure.
Manufacture of three conventional double panels
Drilling-copper plating (hole metallization)-outer circuit (forming pattern resist)-outer etching-solder resist (printing green oil, characters)-surface coating (spraying tin, depositing gold, etc.)-forming (milling and cutting), finished!
See if you feel suddenly enlightened. I believe that you who love to learn will be able to quickly master the production of multilayer board.
