Etching
As the copper thickness increases due to the increasing difficulty of potion exchange, the amount of lateral erosion will become larger and larger. Multiple times are required to reduce the large amount of lateral erosion caused by potion exchange as much as possible. The fast etching method solves the problem. As the amount of side etching increases, it is necessary to compensate for the side etching by increasing the etching compensation coefficient.

Lamination
With the increase in copper thickness, the line gap is deeper. Under the same residual copper rate, the required amount of resin filling needs to increase. It is necessary to use multiple prepregs to meet the problem of filling; due to the need to use resin to maximize. The prepreg with high glue content and good resin fluidity is the first choice for thick copper PCBs.
The commonly used prepregs are 1080 and 106. When designing the inner layer, place copper points and copper blocks in the copper-free area or the final milled area to increase the residual copper rate and reduce the pressure of the glue filling. The increase in the use of prepreg will increase the risk of sliding, and adding rivets is a valid method of strengthening the degree of fixation between the core boards. Under the trend of increasing copper thickness, the resin is also used to fill the blank area between graphics.
Therefore, in PCB manufacturing, choosing a board with fillers, low CTE, and high Td is the basis for ensuring the quality of thick copper PCBs. As the copper is thicker than the board, more heat is required for lamination. Longer temperature conductive times are required, and insufficient duration of high temperature can result in insufficient resin curing of the prepreg. That will lead to a reliability risk for the circuit board; therefore, increasing the duration of the high-temperature section of lamination is highly desirable to ensure the curing effect of the prepreg. If the prepreg is insufficiently cured, the amount of glue removed from the prepreg relative to the core board is large, forming a stepped shape, and then the hole copper is broken due to the action of stress.

Drilling
Thick copper PCBs are usually more than 2.0mm thick. Due to thicker copper thickness during drilling, it is more difficult to make. Segmented drilling has become an effective solution for drilling thick copper plates. In addition, the optimization of drilling-related parameters such as feed speed and retract speed also greatly impacts the quality of the hole. For the problem of milling target holes, when drilling, the X-RAY energy gradually decays with the increase of copper thickness, and its penetration ability will reach the upper limit, making confirming the first board very difficult. The offset confirmation target can be set at different positions on the board’s edge as a backup solution. The offset confirmation target line can be milled out on the copper foil according to the target position when the material is cut. Layer target holes correspond to production. The problem of inner layer thick copper pads (mainly for large holes above 2.5mm) requires thick copper plates, and the inner layer pads are getting smaller and smaller, and the problem of pad cracking during PCB drilling often occurs. There is little room for improvement in such problematic materials. The traditional improvement method is to increase the pad, increase the peel strength of the material, and reduce the drop speed of the drilling hole. From the PCB processing design and process analysis, an improvement plan is proposed: copper extraction (that is, when the pad is etched on the inner layer, the concentric circles smaller than the aperture are etched away) to reduce the pulling force of the drilled copper. Drilling first drills a pilot hole 1.0mm smaller than the hole diameter and then performs normal drilling (that is, perform secondary drilling) to solve the inner layer thick copper pad cracking.