Hi,

At a previous job, I saw a presentation that recommended normal guardrings and *no* area filling of substrate and nwell-taps in unused areas in technologies 180nm and lower. In these technologies, STI exists where active (diffusion) regions were not located.

My question/request is can someone point me to a paper or presentation that documents these recommendations (requirements) and why? I thought the reasoning was for either latch-up immunity or ESD concerns, but I don't recall. A web search has been fruitless so far.

Thanks, Joe