Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

Solder paste for RF boards

Matthew Amidon


Solder paste for RF boards | 15 April, 2002

Does anyone know of a No Clean solder paste that works well with RF boards. I have tried no clean in the past, and the boards have failed miserably

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Solder paste for RF boards | 15 April, 2002

Problems using NC in RF circuits are peculiar. Depending on the situation [ie, circuit layout, frequency of use, processes used, materials, and what not], a particular NC flux may not work with a RF circuit. Various NC fluxes leave different levels of crud on the board that can affect RF performance. This occurs because electromagnetic waves travel closer and closer to the surface of conductors as frequency increases. At higher frequencies, NC res affects this �skin effect� to a greater degree that signals that burrow though conductors, like moles. Consider: * Using a NC flux that you can clean. * Asking your solder paste / flux supplier for recommendations that suit your application.

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Solder paste for RF boards | 15 April, 2002

Everything we do is RF and have had no problems in the last 7 years with - Indium NC-SMQ92J, Sn63 Pb 37, 90.25% Metal, -325+500 mesh. Stencils are always 0.005" thick. However I will qualify that by adding we are an OEM and each new product may require some tinkering with component values after the prototype run. In some cases a change in PCB supplier may also require adjustments, though this is rare for us nowdays. It may not work as well for you if you are a subbie and locked in to the customer's BOM.

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