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

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chemical etching



chemical etching | 16 October, 2002

during the failure analysis, how to etch the tin,nickle,and copper?

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chemical etching | 16 October, 2002

Hey Mar,

Sounds serious!!! Poke around Buehler, Leco, or Struers

Try IPC TM-650 Test Methods Manual: 2.3.6A Etching, Ammonium Persulfate Method - 7/75 2.3.7A Etching, Ferric Chloride Method - 7/75 Cupric Chloride Etching Method - 12/94 Alkaline Etching Method - 12/94

Just so that you know, for 3% hydrogen peroxide, you can mix your own 3% peroxide, if you have the 30%. However we use the 3% available from drug stores.

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chemical etching | 17 October, 2002

We generally etch the copper back slightly using a 50/50 mix of 3% Hydrogen Peroxide and laboratory grade Ammonium Hydroxide. Swab for about 5 seconds, then rinse.

and etch the tin in the solder to further delineate the intermetallic layer that should be done last by immersing the sample in a 2% mixture of Nitric acid and Methanol for about 1 minute.

any detailed information???

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