SOLDER MASK SELECTION FOR SMT BOARDS.

被引：0

作者：

Tilsley, G.M. ^{[1
]}

Axon, F.J. ^{[1
]}

Fisher, Larry ^{[1
]}

机构：

[1] Dynachem Europe, Dynachem Europe

来源：

Circuits manufacturing | 1988年 / 28卷 / 06期

关键词：

SOLDERS; -; Applications;

D O I：

暂无

中图分类号：

学科分类号：

摘要：

Because of the fine tolerances and resolution requirements of SMT work, screen printing of solder mask patterns has been replaced by photo-imageable solder masks. This technology includes two general types: dry-film, where preformed films are laminated to the circuit board, and liquid solder mask systems, where wet films are applied. A liquid solder mask usually provides a coating thickness of 20 to 40 microns in standard processing; if greater thicknesses are desired, special double coating is needed. Dry films are usually 75 to 100 microns thick, although 50 micron materials are also available. With SMT, the solder mask thickness has wide-reaching implications on board design, on the PCB manufacturing process, and on assembly soldering, when a 50 to 75 micron thickness is generally preferred. The authors discuss design and fabrication considerations and the use of mixed technology.

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