Semiconductor Gate-Contact Isolation Layout for Short-Circuit Prevention
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Solution Overview
Problem
As semiconductor devices evolve with smaller dimensions and increased density, the proximity of conductive contacts in the front-end-of-line (FEOL) and metal gates in the middle-of-line (MOL) poses a risk of short circuits, necessitating an improved semiconductor device structure and manufacturing method to prevent such failures.
Innovation Solution
The semiconductor device structure involves forming fins with specific semiconductor layers, using sacrificial gate stacks, spacers, and replacement gate structures, along with a contact etch stop layer and interlayer dielectrics, to create a configuration that minimizes the risk of short circuits by optimizing the placement and isolation of conductive features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature dimensions are reduced to increase device density, then device functionality and performance are improved, but the risk of short circuits between conductive contacts and metal gates increases
Solution Approach 1:
The patent applies preliminary action by forming a mandrel structure and spacer before defining the final conductive contact and gate positions. The mandrel and spacer are temporarily formed to establish precise spacing relationships, then removed and replaced with the final conductive structures. This preliminary structuring ensures that even when features are scaled down, the minimum spacing between conductive contacts and gates is maintained, preventing short circuits while enabling higher device density.
2Productivity
If conductive contacts and metal gates are placed closer to increase density, then device functionality is improved, but manufacturing precision requirements become more stringent
Solution Approach 1:
The patent uses the mandrel and spacer as intermediary structures that simplify the manufacturing process. Instead of directly placing conductive contacts and gates with high precision requirements, the mandrel and spacer serve as temporary mediators that define the spacing relationships. These intermediaries can be formed with relaxed precision requirements, and their removal followed by formation of final structures ensures accurate placement without stringent direct placement precision requirements.
3Productivity
If photolithographic definition capability is reduced due to smaller dimensions, then device density increases, but the ability to define structures accurately deteriorates
Solution Approach 1:
The patent transitions from defining all structures in the planar photolithographic dimension to using vertical spacer formation and mandrel structures. The spacing between features is defined by the vertical thickness of the spacer layer rather than by photolithographic pattern spacing. This dimensional shift allows device density to increase in the planar direction while maintaining accurate feature definition through vertical layer thickness control, which can be achieved with better precision than lateral photolithographic resolution at small dimensions.
Data Source
AI summary
A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes a gate electrode layer disposed over a substrate, a source/drain epitaxial feature disposed over the substrate, a first hard mask layer disposed over the gate electrode layer, and a contact etch stop layer (CESL) disposed over the source/drain epitaxial feature. The structure further includes a first interlayer dielectric (ILD) layer disposed on the CESL and a first treated portion of a second hard mask layer disposed on the CESL and the first ILD layer. A top surface of the first hard mask layer and a top surface of the first treated portion of the second mask layer are substantially coplanar. The structure further includes an etch stop layer disposed on the first hard mask layer and the first treated portion of the second mask layer.