PCB manufacturing is a very complex process. Let professional Shenzhen circuit board manufacturers and flexible circuit board manufacturers share with us the issues that should be paid attention to during the PCB etching process.

1. Reduce lateral erosion and protrusions, and increase etching coefficient
Lateral erosion produces protrusions. Usually, the longer the printed circuit board is exposed to etching solution, the more severe the side corrosion. Side erosion seriously affects the accuracy of printed wires, making it impossible to produce fine wires. When the lateral erosion and protrusion decrease, the etching coefficient increases. A higher etching coefficient indicates the ability to maintain thin wires, making the etched wires closer to the original size. Electroplating, etching, and corrosion inhibitors, whether they are tin lead alloys, tin, tin nickel alloys, or nickel, can cause wire short circuits due to excessive protrusions. Because the protrusion is prone to breakage, an electrical bridge is formed between the two points of the wire.

2. The experience of Shenzhen circuit board manufacturers and flexible circuit board manufacturers tells us that there are many factors that affect side corrosion, and the following are listed one by one:
1) Etching method: Soaking and bubbling etching can cause significant side corrosion, while splashing and spray etching have smaller side corrosion, with spray etching having the best effect.
2) The type of etching solution: Different etching solutions have different chemical components, resulting in different etching rates and etching coefficients. For example, the etching coefficient of acidic copper chloride etching solution is usually 3, while the etching coefficient of alkaline copper chloride etching solution can reach 4. Recent studies have shown that nitric acid based etching systems can achieve almost no side etching, with the etched lines and sidewalls approaching perpendicularity. This etching system is yet to be developed.
3) Etching rate: A slow etching rate can cause severe lateral corrosion. The improvement of etching quality is closely related to the acceleration of etching rate. The faster the etching speed, the shorter the time the board stays in the etching solution, the smaller the lateral etching amount, and the clear and neat etched patterns. This is the result obtained by Shenzhen circuit board manufacturers with rich experience in the production process.
4) The pH value of etching solution: When the pH value of alkaline etching solution is high, the side corrosion increases. In order to reduce lateral erosion, the pH value should generally be controlled below 8.5.
5) Density of etching solution: If the density of alkaline etching solution is too low, it will aggravate side corrosion, as shown in Figure 10-4. Choosing an etching solution with high copper concentration is beneficial for reducing side corrosion.
6) Copper foil thickness: It is best to use (ultra-thin) copper foil for etching thin wires with minimal lateral corrosion. And the thinner the line width, the thinner the copper foil thickness should be. Because the thinner the copper foil, the shorter the time it spends in the etching solution, and the smaller the amount of side etching.

The above is the experience of Shenzhen circuit board manufacturers and flexible circuit board manufacturers that tells us the issues that should be paid attention to during etching. Friends should pay attention to them during the circuit board manufacturing process!