Self-Aligned Contact by Gate Reveal Method
Publication Date: 2016-Jun-23
The IP.com Prior Art Database
Disclosed is a method to use self-planarization materials during Chemical Mechanical Planarization (CMP) to reduce Self-Aligned Contact (SAC) Nit residue from incoming CMP erosion.
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-Aligned Contact by Gate Reveal Method
Aligned Contact by Gate Reveal Method
Chemical Mechanical Planarization (CMP) endpoints on the majority feature on wafer,
which is field oxide. Current Self-Aligned Contact (SAC) CMP leaves thick SAC Nit residue due to planarization end-pointed on field oxide, which has incoming topography (from gate W CMP). The provided incoming HW has localized topography (erosion/dishing).
A solution is needed to overcome localized SAC Nit residue due to incoming CMP erosion.
Figure 1: Illustration of the problem
The novel method uses self-planarization materials (e.g., Organic Planarization Layer (OPL), spin-on glass, flowable Chemical Vapor Deposition (CVD) dielectric) to planarize field oxide first. By revealing the gate structure with planarized sacrificial material, the
with-in-wafer thickness non-uniformity is reduced to a much lower level. This process makes use of Reactive Ion Etching (RIE) selectivity of oxide to nitride and oxide to sacrificial materials.
Figure 2: CMP process end-points on Field oxide
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Figure 3: Prior art vs. proposed solution
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