Thanks for your response, David. We suspect that the plastic is 
susceptible to moisture absorption, especially over a two year storage 
duration. However, the two issues we are really trying to address are:

1. Storage: IPC-SM-786A has 6 levels of classification, which 
depend on the level of susceptibility. To which level should these parts be 
classified? Once classification is defined, then the storage requirements 
listed in IPC-SM-786A are clear.

2. Reliability: Because the parts will be wave soldered the package will not 
be immersed in solder. Can we assume that the soldering temperatures will 
have no impact upon reliability (or yields)? Even after two years storage?

Thanks,
Mike


On Thu, 15 Feb 1996 [log in to unmask] wrote:

>      In response to the original inquiry placed through Mike Buetow, a 
>      manager in our Materials and Processes Laboratories has forwarded the 
>      included response.
>      
>     
>      *****************************************************
>      Name:      David T. Novick
>      Internet:  [log in to unmask]
>      Phone:     714/762-5522
>      Fax:       714/762-2415 or 714/762-4493
>      *****************************************************
>           
>      
> ______________________________ Forward Header ________________________________
> > Subject: Re: long-term storage of DIPs
> > Author:  Leonard R. Enlow at RI_ANA_CC1
> > Date:    2/15/96 1:49 PM
> 
> 
> > Yes the plastic needs special handling.  Refer to IPC-SM-786 "Recommended 
> > Procedures for Handling of Moisture Sensitive Plastic IC Packages".  Prior to 
> > using the parts after they have been stored for a long time, bake them for 24 
> > hours at 125C.
> > Len Enlow, Rockwell - Anaheim
> 
> ******************************Original Inquiry********************************
> 
> >> We have a member who is specifying a large number of a soon-to-be 
> >> discontinued plastic DIP IC. These parts will then be stored up to two 
> >> years at their facility.
>      
> >> His concern is with handling of these parts, particularly how to store 
> >> them (vapor barrier bags, for example?). He is well aware of the 
> >> precautions necessary for SMDs, but doesn't know whether these apply to 
> >> DIPs too. Any advice?
>      
> >> Mike Buetow
> >> IPC Technical Staff
>      
> 
>