Temporary Peelable Blue Mask for selective soldering protection

Peelable Blue Mask is a temporary, liquid photoimageable solder resist ink with excellent peelability in PCB manufacturing. It acts as a "temporary protective shield" in the PCB process. It is coated and cured over areas requiring protection. After relevant process steps (such as Hot Air Solder Leveling (HASL), plating, chemical etching, etc.) are completed, it can be easily removed manually or by machine entirely without damaging the underlying circuitry or substrate.

It is typically blue (hence the name), but other colors exist (e.g., green, red). However, "Blue Mask" is the most generic and common term.

Key Characteristics

◈ 1.Selective Surface Finishing (Most Common Use)
The PCB requires different surface finish processes. For example, gold finger areas may need ENIG (Electroless Nickel Immersion Gold), while other large pad areas require HASL.
Function: First, open windows in areas requiring gold plating, then coat and cure the peelable blue mask over the entire remaining board surface. Proceed with HASL. After HASL, peel off the blue mask, and then perform the gold plating process. This ensures the gold-plated areas are not contaminated by solder.

◈ 2.Protection of Gold Fingers or Specific Areas
During soldering (SMT) or product assembly, use peelable blue mask to cover sensitive areas like gold fingers and connectors to prevent oxidation, flux contamination, or scratches. It is peeled off after assembly is complete.

◈ 3.Preventing Solder Bridging
Applied between very closely spaced pads (e.g., under a QFN chip) to form a barrier, effectively preventing solder short circuits during wave soldering or hand soldering. It is peeled off after soldering.

◈ 4.Localized Protection During Chemical Etching
Protects areas that should not be etched during thick copper etching or special circuit formation.

◈ 5.Protection Before Potting/Conformal Coating
Areas that should not receive conformal coating (e.g., silicone, epoxy) — such as connectors or test points — are covered with peelable blue mask first. After the coating cures, the mask is peeled off, ensuring connector cleanliness and conductivity.