Motoyo Wajima <[log in to unmask]> さんは書きました：
>Mr.Hammond
>
>   A 1:1 aspect ratio of blind via is limit.
>   Vibration through electroless,electro plating process and lower current
>   density in electro plating are very important.
>   Regards
>Motoyo Wajima
>General Purpose Computer Division,Hitachi,Ltd.(JAPAN)
>
>
>[log in to unmask] さんは書きました：
>>     I've heard that the general rule limiting blind vias is a 1:1 aspect 
>>     ratio.  You are at it with the 16 mil holes & 16 mil depth.  It seems 
>>     like you are doing the right things (i.e. vibration, etc.) so I'm not 
>>     sure what else to suggest.
>>     
>>     
>>     MB
>>_____________________________ Reply Separator 
>_________________________________
>>Subject: Blind vias & fine lines
>>Author:  [log in to unmask] at SMTPLINK-HADCO
>>Date:    2/12/97 10:07 PM
>>
>>
>>Techneters,
>>  Can anyone help? I am having two problem areas:
>>     
>> 1) Blind via holes 16 mil diameter 16 mil deep contacting with 4 
>>inner layers. I cannot always plate copper into all holes. If I do copper 
>>plate them I cannot tin plate all the holes. I have vibrators on the 
>>cathode movement frame and a giant to clout the fight bars with a 2 pound 
>>hammer. Is there anything else I can do?!?
>>     
>> 2) Circuits with 2 mil track and gaps. The finish required is 
>>electroless nickel/immersion gold. How can this be done without causing 
>>the tracks to short with nickel spikes?
>>     
>>  Thanks in advance,
>>   Roger Hammond
>>     
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