Werner,

Will cycling the temerature cold put the component under tensile or
compressive load?  To the best of my knowledge ceramic materials (in
general) should have a high tesile strength with a small strain to failure
in comparison with standard isotropic materials.

In a PCB application which base material will win the CTE battle, the
isotropic copper pad and solder that the component is attached to or the
anisotropic laminate that the board is made out of?

Any thoughts?

Scott M. Severson
Benchmark Electronics Inc.

>Date: 18-Jun-98 6:42:43 -0600
>From: ENGELMAI @ SMTP (Werner Engelmaier) [log in to unmask]
>To: TECHNET @ SMTP [log in to unmask]
>Subject: Re: [TN] SMT Reliability
>
>The larger solder fillets resulting from putting 0603 CCs on 0805 pads are
>only a possible reliability problem, if the assembly gets cycled to cold
>temperatures.
>
>Werner Engelmaier
>Engelmaier Associates, L.C.
>Electronic Packaging, Interconnection and Reliability Consulting
>7 Jasmine Run
>Ormond Beach, FL  32174  USA
>Phone: 904-437-8747, Fax: 904-437-8737
>E-mail: [log in to unmask]
>
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