Method of making PCB dielectric layer

Abstract

A method of making a PCB dielectric layer comprises the following steps: choosing two identical prepregs when making a dielectric layer of a multilayer printed circuit board; measuring the longitudinal glass fiber spacing a and the latitudinal glass fiber spacing b of the prepregs; completely overlapping the two identical prepregs, wherein, the longitudinal glass fiber bundles of the two prepregs extend along the X-axis direction, and the latitudinal glass fiber bundles of the two prepregs extend along the Y-axis direction; moving the lower prepreg along the X-axis direction and the Y-axis direction by X1 and Y1 respectively for dislocation, wherein X1 is non-integer times of a, and Y1 is non-integer times of b; pre-stacking the dislocated prepreg and a core board to get a pre-stacked board, coating the surface of the pre-stacked board with copper foil, placing the pre-stacked board on the chassis of a press, hot-pressing the pre-stacked board to form a multilayer board, and drilling, plating and etching the multilayer board to form an impedance controlled circuit. The uniformity of dielectric constant of the dielectric layer can be improved effectively.

Description

technical field [0001] The invention relates to a method for manufacturing a PCB dielectric layer. Background technique [0002] The base material (also known as the dielectric layer) of the printed circuit board is a copper-clad laminate, and the most commonly used FR4 copper-clad laminate is currently made of electronic glass fiber cloth as a reinforcing material. Treated glass fiber cloth, impregnated with resin glue, and then heat-treated (pre-baked) to make the thin sheet material made of resin is called prepreg. One or both sides of the prepreg are covered with copper foil of a certain thickness, and then heated. The sheet-like material formed by pressure treatment is FR4 copper clad laminate. Most of the prepregs used in the production of multilayer printed boards use E-glass fiber cloth (Electrical Glass, E-glass) as a reinforcing material, and E-glass is woven from glass fiber yarn. Due to the large difference in the dielectric constant of resin and glass fiber, t...

AI Technical Summary

Problems solved by technology

When two or more impedance-controlled transmission lines are distributed at different positions on the substrate, the actual dielectric constants of their positions are different, which will lead to a large difference in the mutual impedance, so that different signal lines have different delays. Affects signal transmission quality

At the same time, due to the inconsistency of the dielectric constant at different positions on the same signal line, a certain section of the impedance value is large, and the other section of the impedance value is small, that is, impedance fluctuations occur, which leads to signal reflection and attenuation, resulting in signal transmission distortion.

Images