- Etching mode: immersion and bubble etching will cause larger side erosion, while splash and spray etching will cause smaller side erosion, especially spray etching.
- Etching solution type: different chemical components of different etching solutions lead to different etching rates and etching coefficients. For example, the etching coefficient of acidic copper chloride etching solution is usually 3, while that of alkaline copper chloride etching solution can reach 4.
- Etching rate: slow etching rate will cause serious side etching. The improvement of etching quality is closely related to the acceleration of etching rate. The faster the etching speed is, the shorter the time the board stays in the etching solution, the smaller the amount of side etching, and the clear and orderly etched patterns are the results of FPC cable laying plant in the production process.
- PH value of etching solution: When the PH value of alkaline etching solution is high, the side etching increases. In order to reduce side erosion, the PH value should be controlled below 8.5 in general.
- Etching solution density: If the density of alkaline etching solution is too low, side erosion will be aggravated. It is beneficial to select etching solution with high copper concentration to reduce side erosion.
- Copper foil thickness: to achieve the etching of thin wires with minimum side erosion, it is better to use (ultra) thin copper foil. The thinner the wire width, the thinner the copper foil thickness. Because the thinner the copper foil is, the shorter the time it is in the etching solution, the smaller the amount of side etching.
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