INDUSTRY COMPONENT

Solder Mask

Solder mask is a protective polymer coating applied to printed circuit boards to prevent solder bridging and protect copper traces from oxidation and environmental damage.

Component Specifications

Definition
Solder mask, also known as solder resist, is a thin lacquer-like layer of polymer applied to the copper traces of a printed circuit board (PCB) during manufacturing. Its primary functions include preventing accidental solder bridges between closely spaced conductive elements during assembly, protecting copper traces from oxidation and corrosion, providing electrical insulation, and enhancing the board's durability against mechanical and environmental stresses. The mask is typically applied through screen printing, curtain coating, or liquid photoimageable methods, then cured through UV exposure or thermal processes to form a permanent protective barrier.
Working Principle
Solder mask works by creating a non-conductive, chemically resistant barrier over copper traces on a PCB, leaving only designated areas (pads and vias) exposed for soldering. It prevents solder from adhering to masked areas during wave soldering or reflow processes, ensuring electrical isolation and preventing short circuits. The mask's properties—such as dielectric strength, thermal stability, and adhesion—are engineered to withstand assembly temperatures and environmental conditions while maintaining board integrity.
Materials
Typically composed of epoxy-based resins (e.g., epoxy acrylate), with additives for flexibility, UV resistance, and thermal stability. Common formulations include liquid photoimageable (LPI) solder masks, dry film solder masks, and thermal-cured types. Halogen-free and high-Tg (glass transition temperature) variants are available for specialized applications.
Technical Parameters
  • Color Green (standard), also blue, red, black, white
  • Thickness 15-35 μm
  • Resolution Down to 50 μm line/space
  • Adhesion Strength >1.0 N/mm
  • Thermal Resistance Up to 288°C (for lead-free soldering)
  • Dielectric Strength >40 kV/mm
Standards
ISO 9001, IPC-SM-840, UL 94, IEC 61249-2-21

Industry Taxonomies & Aliases

Commonly used trade names and technical identifiers for Solder Mask.

Parent Products

This component is used in the following industrial products

Engineering Analysis

Risks & Mitigation
  • Incomplete coverage leading to solder bridging
  • Poor adhesion causing delamination
  • Thermal degradation during assembly
  • UV curing inconsistencies
  • Chemical incompatibility with cleaning agents
FMEA Triads
Trigger: Inadequate curing or contamination during application
Failure: Solder mask delamination or blistering
Mitigation: Implement strict process controls, pre-clean surfaces, and verify curing parameters (time, temperature, UV intensity).
Trigger: Misalignment during photolithography
Failure: Exposed copper or masked pads, causing soldering defects
Mitigation: Use high-precision alignment systems, regular calibration, and automated optical inspection (AOI).
Trigger: Material degradation from harsh environments
Failure: Loss of insulation or corrosion protection
Mitigation: Select high-performance materials (e.g., high-Tg, halogen-free) and conduct environmental testing per industry standards.

Industrial Ecosystem

Compatible With

Interchangeable Parts

Compliance & Inspection

Tolerance
±5 μm thickness variation, alignment within ±25 μm
Test Method
IPC-TM-650 for adhesion, dielectric strength, and thermal shock resistance; UL 94 for flammability; ISO 2409 for cross-cut adhesion

Buyer Feedback

★★★★☆ 4.9 / 5.0 (25 reviews)

"Impressive build quality. Especially the technical reliability is very stable during long-term operation."

"As a professional in the Computer, Electronic and Optical Product Manufacturing sector, I confirm this Solder Mask meets all ISO standards."

"Standard OEM quality for Computer, Electronic and Optical Product Manufacturing applications. The Solder Mask arrived with full certification."

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Frequently Asked Questions

What is the difference between solder mask and solder paste?

Solder mask is a permanent protective coating on PCBs to prevent solder bridging, while solder paste is a temporary mixture of solder particles and flux applied to pads before component placement to facilitate soldering.

Why is solder mask typically green?

Green is the traditional color due to historical use of epoxy resins with bromine-based flame retardants, which produced a green hue; it also offers good contrast for inspection. Other colors are now available for branding or functional reasons.

Can solder mask be repaired if damaged?

Yes, minor damage can be repaired using epoxy-based solder mask inks or UV-curable patches, but extensive damage may require board rework or replacement to ensure reliability.

Can I contact factories directly?

Yes, each factory profile provides direct contact information.

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Socket Housing Solder Mask Layer