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Method of forming moat Structure to reduce DT distortion

IP.com Disclosure Number: IPCOM000236380D
Publication Date: 2014-Apr-23
Document File: 3 page(s) / 274K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method of reducing Deep Trench (DT) stress by optimizing moat structure. The simple long moat structure cannot withstand vertical distortion by DT. The method adds a vertical structure, or dividing moat structure, to mitigate the distortion by DT and improve product performance.

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Page 01 of 3

Method of forming moat Structure to reduce DT distortion

From 22S, N+ doped Epitaxial (N+epi) substrate and moat are required for substrate doping and isolation of passive devices. HiK material, including node metal, has high stress during the process. Deep Trench (DT) stress causes an accumulated strain at the edge of the DT array. If there is moat along the DT array, then the DT stress can easily cause a large DT distortion. Large distortion is the major root cause of an Rx to DT short.

Figure 1: Prior Art, the problem

Because the long moat structure along the DT array cannot hold the distortion of array DT, the moat needs to be more structurally robust.

The solution is to divide the moat structure perpendicular to the edge of the array, thereby reducing the DT distortion.

Figure 2: The solution, preferred embodiment

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Page 02 of 3

Figure 3: Real structure of moat

Figure 4: Schematic showing array displacement with moats after Hi-K (Hafnium Silicon Oxygen/Hafnium Oxygen (HfSiO/HfO)) & Titanium Nitride (TiN) dep/anneals

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Figure 5: APDM(Array Patterned DT Monitor)-like macro (without moat): Chip 15

Figure 6: APDM with moat

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