Contents
What is purpose of solder mask?
Solder mask is a thin layer of polymer that is put on a circuit board to protect the copper from oxidation and shorts during operation. It also protects the PCB from environmental influences such as dust and several other contaminants that may lead to shorts in the long run.
What is solder mask expansion?
It is the expanded distance between SMT pads and solder mask layer. In the production of printed circuit board there should be some space for pads on solder mask layer, which avoid the overlapping of solder mask layer and pads.
What is the solder mask layer?
Soldermask is a protective layer of liquid photo image able lacquer applied on the top and bottom side of a Printed Circuit Board. The function of the Soldermask is to protect the copper, apart from the solder pads, from: Oxidation. Creating shorts during. Soldering (bridges)
How is solder mask applied to PCB?
Solder mask is applied to the circuit board through three different media forms, after which it is thermally cured to set and harden it. Next, we will look at what those different media forms are and how they are used.
What is silk to solder mask clearance?
Summary. This rule checks the clearance between any silkscreen primitive and any solder mask primitive or exposed copper-layer primitive (exposed through openings in the solder mask). The check ensures that the distance is equal to or greater than the value specified in the constraint.
What is mask clearance?
Mask clearance is the clearance required for firing the weapon without danger of a premature detonation of the round by obstructions, such as trees, hills, or buildings. After the mortar is mounted, the gunner must determine the minimum and the maximum mask clearance.
What is the difference between solder mask layer and paste mask layer?
2) The solder mask layer is one part on the circuit board, but the paste mask layer is not. Paste mask layer is just for the stencil. 3) Solder mask is used for applying solder mask ink, but paste mask is used for applying paste. 4) Solder mask is applied when making PCB board, but paste mask is used when assembling.
How is the color of the solder mask determined?
The color of your solder mask is determined by the dye used in the solder mask material, and the chemical properties of the dye will influence the cured solder mask thickness. One reason that green solder mask is extensively used is that it can be used to create thin solder mask dams (~0.1 mm).
Can a solder mask be used on a heat sink?
If your IC only dissipates a few watts, keep the silkscreen or use a SMD heat sink. So, if you want to avoid the risk of shorting copper pours, stick with the solder mask. It’s probably lower in thermal resistance than the difference between a pad and a thin layer of heat conducting paste.
How is a dry film solder mask applied?
Dry Film Solder Mask (DFSM) DFSM solder mask is applied using a similar process as LPSM. Both PCB solder mask types are exposed in a photolithography-type process. Rather than being applied as a liquid, the dry film is applied in sheets of solder mask film using a vacuum lamination process.
What should my solder mask thickness be on my PCB?
LPSM and DPSM solder mask thickness in empty areas of the board will generally vary with location. The typical solder mask thickness (perpendicular to the board) is at least 0.8 mils. Solder mask will be thinner near the edges of traces and can reach as thin as 0.3 mils or less.