The solder mask design in PCB processing in Dongguan

The solder mask design in PCB processing in Dongguan

The minimum solder mask gap, minimum solder mask bridge width, and minimum N cover expansion size depend on the solder mask pattern transfer method, surface treatment process and copper thickness. Therefore, if you need more precise solder mask design, you need to know about the PCB board factory.

(1) Under the condition of 1OZ copper thickness, the solder mask gap is greater than or equal to 0.08mm (3mil).

(2) Under the condition of 1OZ copper thickness, the width of the solder mask bridge is greater than or equal to 0.10mm (4mil). Since the lm-Sn solution has an attacking effect on some solder resists, the width of the solder mask bridge needs to be increased moderately when using the surface treatment of the lm-Sn, and the minimum is generally 0.125mm (5mil).

(3) Under the condition of 1OZ copper thickness, the minimum expansion size of the conductor Tm cover is greater than or equal to 0.08mm (3mil).

The solder mask design of the via hole is an important part of the PCBA process manufacturability design. Whether to plug holes depends on the process path and the layout of the vias.

(1) There are three main methods for solder mask of via holes: plug hole (including half plug and full plug), open small window and open full window.

(2) Solder mask design of via holes under BGA

For the solder mask of BGA dog bone connection via holes, we prefer plug hole design. This has two advantages. One is that it is not easy to bridge due to the offset of the solder mask during BGA reflow soldering; the other is that if the bottom surface of the BGA directly passes the wave crest, it can reduce the soldering and soldering during wave soldering. Melt, affecting reliability.