Kathy

See below for answers on silver migration

1 - Humidity aids silver migration

2 - Yes, one cause is cracked flash on the component leads exposing the
silver and allowing diffusion. Possible on resistor array networks, I
have seen 1 off component of this type fail for this reason. The vendor
admitted they had a small problem and had changed the manufacturing
process. I have also seen it on another device type with multiple
failures

3 - Yes, obviously!

4 - Not sure if public, certainly device vendors will have data if they
have suffered problems. We conducted our own research using 3rd party
agents. None of the research revealed manufacturing faults at the
component assembly (into pcb)stage.

Changing the pitch will alleviate the symptoms of diffusion (but for how
long?, but does not address the causes.

Best Regards

Ian Boyton


>From: Kathy Palumbo <[log in to unmask]>
>Reply-To: "TechNet E-Mail Forum." <[log in to unmask]>,Kathy Palumbo
<[log in to unmask]>
>To: [log in to unmask]
>Subject: [TN] Silver Migration
>Date: Wed, 24 Mar 1999 11:10:17 -0800
>From [log in to unmask] Wed Mar 24 11:11:55 1999
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>Can anyone help me?
>
>> I have been told by a chip component manufacturer that the reason
they
>> changed the pin out on a resistor network from a concave to a convex
was
>> because it allowed them to place the pin terminations farther away
from
>> one another, which in turn helped to reduce the issue of silver
migration.
>>
>> My questions are:
>>
>> 1.  What are the conditions that silver migration can occur?
>>
>> 2.  Could these conditions be present in chip components, particulary
>> resistor array networks?
>>
>> 3.  Has anyone ever heard of this or had issues with this?
>>
>> 4.  Is there any supporting research to back this claim?
>>
>> Thanks in advance for you support.
>>
>> Kathy Palumbo
>
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