Semiconductor Gate Protection Layer Prevents Interconnect Shorts
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Solution Overview
Problem
The challenge in semiconductor device manufacturing lies in aligning interconnect plugs with source/drain terminals while avoiding overlap with gate terminals, which can cause circuit shortages due to the larger size of interconnect plugs and unintentional shifting, especially as devices shrink in size.
Innovation Solution
A protection layer is deposited over the gate structures, which covers at least a portion of the gate electrodes and sidewall spacers, creating a barrier between the interconnect plugs and the gate electrodes, thereby preventing electrical connection and reducing the likelihood of circuit shorts. This layer has a high selectivity in etching processes and is designed to be partially conformal to the gate structures, allowing for precise alignment and reduced overlap risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If interconnect plugs are made larger to meet performance requirements, then electrical connection reliability is improved, but alignment precision with source/drain terminals deteriorates and overlap with gate terminals increases
Solution Approach 1:
A protection layer is introduced as an intermediary between the interconnect plug and the gate terminal. This protection layer acts as a physical barrier that prevents direct contact and potential short circuits between the larger interconnect plug and the gate terminal, thereby maintaining electrical connection reliability while accommodating the size increase of interconnect plugs
Solution Approach 2:
The protection layer is formed in advance before the interconnect plug is created. By pre-forming the protection layer over the gate terminal, the structure is prepared to receive the larger interconnect plug without risk of overlap-induced short circuits, thus enabling improved electrical connection reliability while maintaining manufacturing feasibility
2Area of moving object
If device size is reduced to continue scaling, then integration density is improved, but the risk of interconnect plug overlap with gate terminal increases due to smaller tolerances
Solution Approach 1:
The protection layer serves as a mediator that decouples the scaling relationship between device size and interconnect plug size. By introducing this protective barrier, smaller devices can accommodate relatively larger interconnect plugs without increased short circuit risk, as the protection layer compensates for reduced alignment tolerances
Solution Approach 2:
The protection layer provides a cushioning effect by creating a safety margin between the interconnect plug and gate terminal. This pre-established protective barrier compensates for the reduced tolerance margins inherent in scaled-down devices, maintaining reliability despite smaller device dimensions
Data Source
AI summary
A semiconductor device includes a gate structure on a substrate; a protection layer on the gate structure; a source/drain region adjacent to the gate structure; and an interconnect plug on the source/drain region. The gate structure includes a gate electrode including a top surface; and a sidewall spacer interfacing a sidewall of the gate electrode. The protection layer covers at least a first portion of the top surface and the sidewall spacer. The protection layer is interposed between the interconnect plug and the gate electrode.