The photoresist must have good adhesion to the surface of the copper foil substrate to ensure the stability of the graphics during subsequent etching and processing.
Resistance to Etching: The photoresist needs to have sufficient etch resistance during the etching process to protect the unexposed area from the etching solution.
Surface Tension: The surface tension of the photoresist affects its fluidity and coverage during coating, and proper surface tension helps form a uniform photoresist layer.
Exposure Speed: Exposure speed determines the productivity of the photolithography process. Fast exposure can shorten the production cycle and increase yield.
Pinhole Density: Pinholes are very small-sized cavities in the photoresist layer, and the lower the pinhole density, the better the uniformity and integrity of the photoresist layer.

The Role of PCB Lithography:
Pattern Transfer: The photoresist accurately copies the circuit graphics on the mask plate to the copper-clad substrate of the PCB through a photochemical reaction.
Protection of the Copper Layer: During the etching process, the photoresist layer protects the unexposed copper layer from being removed by the etchant, thus forming the desired circuit pattern.
Improve Production Efficiency: The high efficiency of the photolithography process has a direct impact on the overall yield and cost of PCB manufacturing.
Ensure Circuit Performance: A precise lithography process ensures the accuracy of the circuit pattern, thus ensuring circuit performance and reliability.
Adapt to Complex Designs: High-performance photoresists can be adapted to increasingly complex circuit designs, to meet the needs of electronic equipment miniaturization, functional diversification.
Environmentally Friendly: Modern photoresist materials and processes tend to be environmentally friendly, reducing the use and emission of harmful chemicals.
Multi-layer Alignment: In multi-layer PCB manufacturing, photoresists require precise alignment capabilities to ensure that circuit graphics between different layers are accurately aligned.
Automated Production: A high level of automation in the photolithography process reduces human error and improves production consistency.
In summary, PCB lithography is a critical step in PCB manufacturing, which directly affects product quality and performance. High-performance photoresists and advanced lithography processes are the basis for realizing high-precision, high-density PCB manufacturing.