FinFET Gate Protection Layer for Short-Range Contact Isolation
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Solution Overview
Problem
As semiconductor technology nodes shrink, forming contacts for FinFET devices becomes challenging due to the increasingly short distance between adjacent device features, leading to potential short-circuit issues caused by thinner dielectric layers between contacts.
Innovation Solution
A dielectric protection layer is formed over the gate trench to ensure electrical isolation between contacts, even when the interlayer dielectric layer becomes thinner or penetrable, by extending along the inner sidewalls of the gate trench and overlaying the top surface of the active gate structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the interlayer dielectric layer thickness is reduced to accommodate smaller feature sizes, then integration density improves, but electrical isolation between contacts deteriorates leading to short-circuit risks
Solution Approach 1:
The dielectric protection layer extends vertically along the inner sidewalls of the gate trench, adding a vertical dimension to the isolation structure. This allows the isolation function to be maintained even when the horizontal dielectric layer thickness is reduced, effectively solving the contradiction between reduced feature size and maintained electrical isolation.
Solution Approach 2:
The dielectric protection layer acts as an intermediary structure between adjacent contacts, providing an additional isolation barrier. This intermediary layer ensures that even when the primary interlayer dielectric becomes thinner, electrical isolation is maintained through the protective dielectric layer that lines the gate trench sidewalls.
2Area of stationary object
If the distance between adjacent device features is reduced to increase integration density, then more components fit in a given area, but the risk of short-circuits between contacts increases
Solution Approach 1:
By extending the dielectric protection layer vertically along the gate trench sidewalls, the isolation structure utilizes the vertical dimension to maintain electrical separation. This allows horizontal feature spacing to be reduced while the vertical extension of the protection layer continues to prevent short-circuits between adjacent contacts.
Solution Approach 2:
The dielectric protection layer segments the gate trench into isolated regions, creating distinct electrical zones between adjacent contacts. This segmentation ensures that even when features are closely spaced, each contact remains electrically isolated by the dielectric barriers formed along the trench sidewalls.
Data Source
AI summary
A semiconductor device is disclosed. The semiconductor device includes a semiconductor fin. The semiconductor device includes a gate spacer over the semiconductor fin. A lower portion of the gate spacer surrounds a first region and an upper portion of the gate spacer surrounds a second region. The semiconductor device includes a gate dielectric within the first region. The semiconductor device includes a metal gate within the first region. The semiconductor device includes a dielectric protection layer, in contact with the gate dielectric layer, that includes a first portion within the second region and a second portion lining a top surface of the metal gate.