Title :
A Novel Approach to Analyze and Model Feature Size Effects in CMP
Author :
Urbach, Jan-Peter ; Rzehak, Roland
Abstract :
In order to characterize and model the pitch dependency of the step-height decay in a typical oxide CMP process, we measured surface profiles for line-space patterns at 50% density but different pitches. The profiles are analyzed in the spatial frequency domain. For long polishing times, we find a linear dependency between the exponential decay rate and the spatial frequency. From this observation, we derive a simple mathematical model to calculate the post-CMP topography based on the layout density. Application to a typical DRAM metalization layer shows remarkably good qualitative agreement with an error in the predicted heights of plusmn15 nm.
Keywords :
DRAM chips; chemical mechanical polishing; integrated circuit metallisation; surface topography measurement; DRAM metalization layer; chemical-mechanical polishing; exponential decay rate; layout density; line-space patterns; mathematical model; post-CMP topography; spatial frequency domain; surface profiles; Chemical–mechanical planarization; design rules; modeling; pattern dependence; semiconductor technology;
Journal_Title :
Semiconductor Manufacturing, IEEE Transactions on
DOI :
10.1109/TSM.2009.2031791
