Dear Vaughan,
It is a very good brainstorming practice. I appreciate very much. But
how to measure the before and after (hi/low) to tell the etch depth. Our
CMM can only measure up to 0.00001". But the depth is 0.00001-0.00003. We
need to consider the tolerance of the CMM as well which reflect the reading
accuracy.
_____________________________________________________________
At 06:00 AM 1999/4/22 -0700, Vaughan, Ralph H wrote:
>Hi Albert,
>
>I don't have a complete answer for you but in my normal keep-it-simple
>methodology, could you not take your copper surfaced control board, mask
>areas or patterns (stripes or checkerboard for example) on the surface, then
>etch. When you de-mask, you will have adjacent hi/low surfaces that can
>be compared.
>
>Just a thought.
>
>Ralph Vaughan
>Boeing-Atlanta
>
>> ----------
>> From: Albert Mok[SMTP:[log in to unmask]]
>> Reply To: TechNet E-Mail Forum.;Albert Mok
>> Sent: Thursday, April 22, 1999 4:40 AM
>> To: [log in to unmask]
>> Subject: [TN] Microetch depth measurement
>>
>> Dear technetters, good morning,
>>
>> Many board shops required microetch process, which is normal the
>> pretreatment/pre-cleaning of copper surface prior to subsequent chemical
>> processes. We have to control the etch depth, either from the spray
>> system,
>> or the batch wise bath from autoplating line. The desired etch depth
>> varies from process for process but ranging from 20-50 microinch.
>>
>> We are using one sq. ft. bare board for the etch testing so that the etch
>> depth is calculated when we based on the fact that 1 microinch is 0.02g of
>> copper for one side.
>>
>> We hope to collect ideas or to gain your experience for getting this
>> results more wisely. We tried of weighing the board, etch, clean and
>> weigh
>> it again. We are thinking to make some tools for this test so as to make
>> the control more easily. We hope to plate copper at a control thickness of
>> 30 microinch and use this as a specimen for the control test or to find a
>> way telling the etch depth by co-relation. We cannot consider the etch
>> chemicals condition since the batch wise and spray application are two
>> extremes.
>>
>> Please kindly offer your ideas and chat.
>>
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>
>
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