Semiconductor Gate Structure With Protected Fin Isolation
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Solution Overview
Problem
Dielectric fin structures in semiconductor devices are vulnerable to damage during metal gate etching processes, compromising electrical isolation and leading to IC failures.
Innovation Solution
A fabrication method and structure that includes a transistor gate structure with a high-k gate dielectric and gate metal stack, and a fin isolation structure with a low-k dielectric layer, protected by a high-k dielectric layer, to enhance the integrity of the fin isolation and gate spacer, preventing transistor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If metal gate etching process is performed, then gate structure is formed, but fin isolation structure is damaged
Solution Approach 1:
A protective dielectric layer is introduced as an intermediary between the metal gate etching process and the fin isolation structure. This protective layer acts as a mediator that allows the etching process to proceed while preventing direct contact between the etchant and the fin isolation structure, thereby maintaining electrical isolation integrity.
Solution Approach 2:
The protective dielectric layer is deposited on the fin isolation structure before the metal gate etching process begins. This preliminary protective action ensures that when the etching process occurs, the fin isolation structure is already shielded, preventing damage before it can happen.
2Reliability
If fin isolation structure is protected, then electrical isolation is maintained, but manufacturing process complexity increases
Solution Approach 1:
The protective dielectric layer serves multiple functions: it protects the fin isolation structure during etching, provides a planar surface for subsequent processing, and can serve as part of the final device structure. This multi-functionality reduces the need for additional dedicated protective layers, thereby limiting the increase in manufacturing complexity.
Data Source
AI summary
The present disclosure describes semiconductor structure and a method for forming the same. The semiconductor structure can include a substrate and a gate structure over the substrate, where the gate structure can include two opposing spacers, a dielectric layer formed on side surfaces of the two opposing spacers, and a gate metal stack formed over the dielectric layer. A top surface of the gate metal stack can be below a top surface of the dielectric layer. An example benefit of the semiconductor structure is to improve structure integrity of tight-pitch transistors in integrated circuits.