[TowerTalk] 31 mix variability ... lost processes

[jimlux]

On 7/9/16 12:09 PM, David Gilbert wrote:
>
> It doesn't even have to be the fault of the receiving entity, whether
> that be a new location or new owners.  I worked in the semiconductor
> industry for over 30 years and saw several examples of "lost recipes"
> simply because the original process was never properly investigated,
> characterized, and documented in the first place.  Processes that had
> produced excellent product for years might suddenly shift because some
> influence that had never been understood at all changed.
>
> We actually had one product that shifted dramatically for the worse
> because a piece of equipment was upgraded to a cleaner version, and it
> took a lot of engineering work to understand the favorable impact that
> the carrier lifetime killing effect from the older, dirtier equipment
> had on the product.
>


You hear a lot of stories about trace contaminants making electron gun 
cathodes "work" or not.  Someone gives up smoking, and all of a sudden, 
things don't work the same as they used to.