PCB surface OSP tin spraying treatment method

Abstract

The application discloses a PCB surface OSP tin spraying treatment method, comprising: adopting 8-layer laminated structure of halogen-free flame-retardant glass fiber substrate; realizing minimum aperture 0.40 mil through fine control of drilling process; after resin grinding, the ratio of copper surface roughness Ra value 1.8-2.2 mu m to OSP film thickness 0.5-0.7 mu m is 0.35-0.45; OSP treatment pH value 2.6-2.8, temperature 39-41 DEG C, within 2 hours after treatment, activation is carried out, within 4 hours, preheating is carried out; after activation treatment, the copper surface contact angle is less than or equal to 85 DEG; tin spraying temperature is 260-270 DEG C, time is 4-6 seconds, after tin spraying, intermetallic compound IMC layer thickness is 1.5-2.5 mu m; preheating temperature and time have corresponding relationship. The application solves the technical problems of insufficient manufacturing precision of existing 8-layer blind buried hole PCB, inaccurate OSP process parameter control and difficult IMC layer thickness control.

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