Loddemaske

Loddemaske is the Danish term for solder mask, a thin polymer layer used in printed circuit board (PCB) fabrication. It is applied to copper traces to insulate areas not intended for soldering, protect copper from corrosion, and prevent solder bridges during assembly. Although green remains the most common color, solder mask can be produced in various colors for identification or aesthetic reasons.

There are two principal types: liquid photoimageable solder mask (LPI) and dry-film solder mask. LPI is applied as a liquid and cured by UV exposure, enabling fine features and high circuit density; dry-film masks are laminated as pre-formed films. Typical mask thickness is about 15 to 25 micrometers. Openings in the mask define pads and vias; pads may be designed as solder mask-defined (SMD) or non-solder mask-defined (NSMD), affecting pad geometry and solderability.

The mask is usually applied after copper etching and cleaning. In LPI processes, a photosensitive layer is exposed through an artwork pattern and developed to reveal copper pads. The layer is then cured to form a durable protective coating. In dry-film processes, the film is laminated, exposed, and developed similarly.

Loddemaske provides electrical insulation, mechanical protection, and aids automated assembly. It is a standard feature of modern PCB fabrication, with materials and processes that balance solderability, inspection, and rework considerations.